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The drug sildenafil (Viagra, Pfizer) and, more recently, tadalafil (Cialis, Lilly-Icos) and vardenafil (Levitra, Bayer), has drawn public attention to aphrodisiacs. The search for such substances dates back millennia. Adverse effects associated with these drugs include hypotension, tachycardia, headache, flushing, blurred vision, dyspepsia, and musculoskeletal pain. Although sildenafil has been marketed for erection of the penis, recent attention has been paid to its application for women, including enhancement of success of in vitro fertilization but also better sexual responses (increased desire, satisfaction, and orgasm) in cases of sexual disorders. Today, there is a debate on internet forums about the potential properties of sildenafil to enhance women's sexual pleasure. This laboratory was asked to analyze a 12-cm length of light brown hair submitted by a British police force following an allegation that a young female had been subjected to sexual assaults over a two-year period. The female was 15-17 years of age at the time. The alleged perpetrator was her stepfather, and there was some suspicion that drugs may have been administered to facilitate the attacks. After decontamination and segmentation (6 x 2-cm section), the specimen was analyzed by liquid chromatography coupled with tandem mass spectrometry after alkaline (pH 9.5) extraction using dichloromethane/ isopropanol/n-heptane (25:10:65, v/v/v). The limit of quantitation was 5 pg/mg. The proximal segment tested positive for sildenafil at 38 pg/mg, and all others proved negative. This was in accord with the victim's claim. In the absence of any controlled studies, it was impossible to put any quantitative interpretation on the measured concentration.

Saliva or "oral fluid" has been presented as an alternative matrix to establish drug exposure. The noninvasive collection of an oral fluid sample, which is relatively easy to perform and can be achieved under close supervision, is one of the most important benefits when testing for driving under the influence of drugs. Moreover, the detection of Delta9-tetrahydrocannabinol (THC) in oral fluid is a better indication of recent use than a positive urine test, so there is a higher probability that the subject is experiencing pharmacological effects at the time of sampling. Twenty-five subjects (5 free and 20 addicts from a heroin detoxification center) were included in a study to evaluate the potential application of a new device, the Cozart DDSV (drug detection system visual), to detect cannabis in oral fluid. The time cannabis was last smoked was recorded by the medical staff after interview with each subject. Samples were collected with the Cozart DDS Oral Swab and diluted with the Cozart DDS buffer as proposed by the manufacturer. The Cozart DDSV test was conducted on site at the time of collection, and the remainder of the sample retained for confirmation analysis by gas chromatography with mass spectrometry (GC/MS) after methylation of THC (limit of quantitation 0.5 ng/mL). All 25 samples were analyzed by GC/MS. On-site results were obtained within 10 minutes. The 5 drug-free subjects were negative for cannabis, irrespective of the method. From the 20 subjects declaring that they had smoked cannabis between 30 minutes and 24 hours previously, the DDSV device identified 8 positive subjects (with THC concentrations in the buffer in the range 15-219 ng/mL), whereas 18 subjects tested positive using GC/MS. THC concentrations in the Cozart buffer using GC/MS analysis ranged from 0.7 to 219 ng/mL. These concentrations represent about one third the authentic THC concentrations in oral fluid due to the dilution by the liquid of the device. Given the results, the DDSV device was considered as an acceptable tool to detect cannabis abuse in oral fluid within a period of 2-3 hours after smoking.

This work presents the validation of a new immunological assay, the One-Step enzyme-linked immunosorbent assay (ELISA) tests from International Diagnostic Systems Corp. for the screening of drugs of abuse (cannabis, amphetamines, opiates, and cocaine) in human hair, with subsequent GC-MS confirmation. After decontamination and segmentation into small pieces, 50 mg of hair sample were incubated in 1 ml of methanol during 16 h at 40 degrees C. A 100 microL aliquot was collected and evaporated to dryness in presence of 100 microL of methanol/hydrochloric acid (99:1, v/v) to avoid amphetamines loss. The dried extract was dissolved in 100 microL of the "sample and standard diluent" solution included in the kit. This solution was submitted to analysis according to the recommended instructions of the manufacturer. During the validation phase, GC-MS confirmations were conducted according to our fully validated and published methods for opiates, cocaine, cannabis, and amphetamines determinations in hair. In a last development step, these procedures were slightly modified to directly confirm ELISA results by GC-MS using the methanolic extract. Ninety-three specimens were simultaneously screened by the ELISA tests (103 for tetrahydrocannabinol (THC)) and confirmed by GC-MS. Twenty were found positive for cannabis (THC: 0.10-6.50 ng/mg), 21 for cocaine (0.50-55.20 ng/mg), 24 for opiates (6-acetylmorphine (6-AM): 0.20-11.60 ng/mg, MOR: 0.20-8.90 ng/mg, codeine (COD): 0.20-5.90 ng/mg), and 13 for amphetamines (AP: 0.20 and 0.27 ng/mg, methamphetamine (MAP): 0.30 and 1.10 ng/mg, methylenedioxymethamphetamine (MDMA): 0.22-17.80 ng/mg). No false negative results were observed according to the Society of Hair Testing's (SoHT) cutoffs (0.5 ng/mg for cocaine, 0.2 ng/mg for opiates and amphetamines, and 0.1 ng/mg for THC). The One-Step ELISA kits appear suitable due to their sensitivity and specificity for drug of abuse screening in hair. This technology should find interest in workplace drug testing or driving license regranting, especially when many samples have to be tested with a high rate of negative samples, as ELISA is an easy and high-throughput method.

A method for clenbuterol determination in hair has been developed. Hair specimens collected from two calves were decontaminated using hot water followed by methylene chloride. Hair was cut into small pieces, and 100 mg was incubated in 1 mL 0.1M hydrochloric acid overnight at 45 degrees C in the presence of 1 ng acebutolol used as internal standard. After neutralization with 1 mL 0.1M NaOH, 2 mL of bicarbonate buffer (pH 8.6) were added and the preparation was then purified using solid-phase extraction with an Isolute C18 column. Methanolic eluent was evaporated to dryness and the residue was reconstituted with 50 microL methanol. A 5-microL portion was injected onto an ACQUITY UPLC BEH C18 column (2.1 x 50 mm, 1.7 microm) and separation was achieved using a gradient of acetonitrile and formate buffer delivered at a flow rate of 0.6 mL/min. Detection was done on a Waters Micromass Quattro Micro API triple-quadrupole mass spectrometer. Ionization was achieved using electrospray in positive mode. Clenbuterol was identified by two transitions (m/z 277.1 > 203.2 and m/z 277.1 > 132.1). Quantitation was performed with the most intensive transition (m/z 277.1 > 203.2) versus the internal standard monitored using the transition (m/z 337.3 > 116.1). When compared with gas chromatography methods that are generally used for the determination of beta-adrenergics, the major advantages of this method were the sensitivity, a shorter run time, and the absence of a derivatization step. The analysis of two hair samples from calves suspected of drug administration showed low clenbuterol concentrations at 3.6 and 4.8 pg/mg.

Saliva or "oral fluid" has been presented as an alternative matrix to document drug use. The non-invasive collection of a saliva sample, which is relatively easy to perform and can be achieved under close supervision, is one of the most important benefits in a driving under the influence situation. Moreover, the presence of Delta9-tetrahydrocannabinol (THC) in oral fluid is a better indication of recent use than when 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) is detected in urine, so there is a higher probability that the subject is experiencing pharmacological effects at the time of sampling. In the first part of the study, 27 drug addicts were tested for the presence of THC using the OraLine IV s.a.t. device to establish the potential of this new on-site DOA detection technique. In parallel, oral fluid was collected with the Intercept DOA Oral Specimen Collection device and tested for THC by gas chromatography mass spectrometry (GC/MS) after methylation for THC (limit of quantification: 1 ng/mL). The OraLine device correctly identified nine saliva specimens positive for cannabis with THC concentrations ranging from 3 to 265 ng/mL, but remained negative in four other samples where low THC concentrations were detected by GC/MS (1-13 ng/mL). One false positive was noted. Secondly, two male subjects were screened in saliva using the OraLine and Intercept devices after consumption of a single cannabis cigarette containing 25mg of THC. Saliva was first tested with the OraLine device and then collected with the Intercept device for GC/MS confirmation. In one subject, the OraLine on-site test was positive for THC for 2 h following drug intake with THC concentrations decreasing from 196 to 16 ng/mL, while the test remained positive for 1.5 h for the second subject (THC concentrations ranging from 199 to 11 ng/mL). These preliminary results obtained with the OraLine IV s.a.t. device indicate more encouraging data for the detection of THC using on-site tests than previous evaluations.

Datura inoxia belongs to the family of Solanaceae. This is a very common plant in New Caledonia that contains two main toxic alkaloids, l-atropine and l-scopolamine. In this study, we report the case of a 20-year-old male admitted to an Emergency Unit after consumption of 6 dried flowers in hot water for hallucinations, mydriasis, and agitation associated with tachycardia and increase of systolic blood pressure to 180. Full recovery was observed after one week. Three weeks later, a lock of about 80 hairs (200 mg) was collected from the subject in vertex posterior with scissors to be tested for both atropine and scopolamine. After decontamination with dichloromethane, a strand of hair was segmented into three parts, cut into small segments (< 1 mm), incubated overnight in 1 mL pH 8.4 phosphate buffer in the presence of 2.5 ng atropine-d(3), the internal standard, then extracted with 5 mL dichloromethane/isopropanol/n-heptane (50:17:33). The residue was reconstituted in 100 microL of methanol, from which 10 microL was injected into an XTerra MS C18 column (100 x 2.1 mm, 3.5 microm) eluted with a gradient of acetonitrile and formate buffer delivered at a flow rate of 0.2 mL/min. A Quattro Micro triple-quadrupole mass spectrometer (MS) was used for analyses. Ionization was achieved using electrospray in the positive ionization mode. For each compound, detection was related to two daughter ions (atropine: m/z 290.2 to 124.0 and 92.9; atropine-d(3): m/z 293.1 to 127.0 and 92.9; scopolamine: m/z 304.1 to 138.0 and 156.0). Although atropine was never detected (limit of detection = 2 pg/mg), scopolamine was identified in the three segments, in the range 14 to 48 pg/mg. The absence of atropine in hair is consistent with its very low dosage in the flower of Datura inoxia. Hair segmentation indicated that the subject was previously exposed on several occasions to the plant. Liquid chromatography-tandem MS appears to be a necessity for testing tropane alkaloids of the Datura group, given the low concentrations to be measured.

Given the limitations of self-reports on drug use, testing for drugs of abuse is important for most clinical and forensic toxicological situations, both for assessing the reality of the intoxication and for evaluation of the level of drug impairment. It is generally accepted that chemical testing of biological fluids is the most objective means of diagnosis of drug use. The presence of a drug analyte in a biological specimen can be used to document exposure. The standard in drug testing is the immunoassay screen, followed by the gas chromatographic-mass spectrometric confirmation conducted on a urine sample. In recent years, remarkable advances in sensitive analytical techniques have enabled the analysis of drugs in unconventional biological specimens such as hair. The advantages of this sample over traditional media, like urine and blood, are obvious: collection is noninvasive, relatively easy to perform, and in forensic situations it may be achieved under close supervision of law enforcement officers to prevent adulteration or substitution. The window of drug detection is dramatically extended to weeks, months or even years when testing hair. It seems that the value of alternative specimen analysis for the identification of drug users is steadily gaining recognition. This can be seen from its growing use in preemployment screening, in forensic sciences, in clinical applications and for doping control. Hair analysis may be a useful adjunct to conventional drug testing in urine. Methods for evading urinalysis do not affect hair analysis. The aim of this review is to document toxicological applications of hair analysis in drug detection.

Saliva or "oral fluid" has been presented as an alternative matrix in the establishment of drug exposure. The noninvasive collection of a saliva sample, which is relatively easy to perform and can be achieved under close supervision, is one of the most important benefits in a driving under the influence situation. Moreover, the presence of delta9-tetrahydrocannabinol (THC) in oral fluid is a better indication of recent use than when the drug is detected in urine, so there is a higher probability that the subject is experiencing pharmacological effects at the time of sampling. At 3 check points organized by the Swiss police in Bern, 61 drivers were tested for the presence of drugs of abuse using the Drugwipe 5 device. In parallel, oral fluid was collected with the Intercept DOA Oral Specimen Collection device and tested by gas chromatography-mass spectrometry (GC-MS) after methylation of THC (limit of quantitation 1 ng/mL). The Drugwipe device identified 1 exposed driver, but with GC-MS, 18 drivers tested positive. THC concentrations in the Intercept buffer ranged from 2.1 to 205.1 ng/mL. These concentrations represent about 1/2 to 1/3 the authentic THC concentrations in oral fluid because of the dilution by the blue liquid of the device. Two main limitations of oral fluid were 1. the amount of matrix collected is smaller when compared to urine and 2. the levels of drugs in urine are higher than in oral fluid. A current limitation of the use of this specimen for roadside testing is the absence of a suitable immunoassay that detects the parent compound in sufficiently low concentrations.

A procedure is presented for the screening of 17 benzodiazepines and hypnotics in oral fluid after collection with the Intercept(R) device by LC-MS/MS (alprazolam, 7-aminoclonazepam, 7-aminoflunitrazepam, bromazepam, clobazam, diazepam, lorazepam, lormetazepam, midazolam, nordiazepam, oxazepam, temazepam, tetrazepam, triazolam, zaleplon, zopiclone and zolpidem). The method involves extraction of 0.5 mL of oral fluid (previously stored in the Intercept blue buffer) treated with 0.5 mL of phosphate buffer (pH 8.4) in the presence of 5 ng diazepam-d(5) used as internal standard, with 3 mL of diethyl ether/methylene chloride (50/50) and separation using liquid chromatography-tandem mass spectrometry. The limits of quantification for all benzodiazepines and hypnotics range from 0.1 to 0.2 ng/mL. Linearity is observed from the limit of quantification of each compound to 20 ng/mL (r(2)>0.99). Coefficients of variation at 2 ng/mL, measured on 6 points range from 4 to 8% for all drugs, except zopiclone (34%). Extraction recovery, measured at the same concentration was higher than 90%. Ion suppression was evaluated for each compound and was lower than 10% for all drugs except zopiclone (93%). These results were found suitable to screen for 17 benzodiazepines in oral fluid and detect them at very low concentrations, making this method suitable for monitoring subjects under the influence.

The use of a drug to modify a person's behavior for criminal gain is not a recent phenomenon. However, the recent increase in reports of drug-facilitated crimes (sexual assault, robbery) has caused alarm in the general public. Drugs involved can be pharmaceuticals, such as benzodiazepines (flunitrazepam, lorazepam, etc.), hypnotics (zopiclone, zolpidem), sedatives (neuroleptics, some histamine H1-antagonists) or anaesthetics (gamma-hydroxybutyrate, ketamine), drugs of abuse, such as cannabis, ecstasy or lysergide, or more often ethanol. Drugs said to be used to facilitate sexual assaults can be difficult to detect (active products at low dosages, chemical instability), possess amnesic properties and can be rapidly cleared from the body (short half-life). We present here a case involving a 23-year old girl that declared a sexual assault 6 days after the event was said to have occurred. To the Police, the victim claimed a total amnesia of the offense associated with intense sedation. Toxicological analyses for unknown sedative drugs achieved by LC-MS/MS revealed the presence of zolpidem (Stilnox), a non-benzodiazepine hypnotic. Concentrations after 6 days were 16 and 32 pg/mL in blood and urine, respectively. The drug tested also positive in the corresponding hair segment at 0.75 pg/mg. The requested extraordinary sensitivity of LC-MS/MS appears as a pre-requisite to document any case involving drug-facilitated sexual assault.

The use of a drug to modify a person's behaviour for criminal gain is not a recent phenomenon. However, the recent increase in reports of drug-facilitated crimes (sexual assault, robbery) has caused alarm in the general public. The drugs involved can be difficult to detect due to low dosages or chemical instability. They possess amnesic properties and can be quickly cleared from the body fluids. In these situations, blood or even urine can be of poor interest. This is the reason why this laboratory developed an original approach based on hair testing by LC-MS/MS. Zopiclone (Imovane), due to its short half-life associated with rapid hypnotic activity, is considered as a compound of choice to sedate victims. To document the detection of zopiclone in hair, we first tested specimens obtained from two volunteers who had ingested a single 7.5 mg Imovane tablet, and from repetitive consumers of zopiclone. After pH 8.4 buffer incubation and extraction with methylene chloride/diethyl ether (80/20 (v/v)), hair extracts were separated on a Xterra MS C18 column using a gradient of acetonitrile and formate buffer. Zopiclone and diazepam-d5, used as internal standard, were detected by tandem mass spectrometry. A single exposure to zopiclone was detectable in the first hair segment of two volunteers at concentration of 5.4 and 9.0 pg/mg, respectively. Hair from repetitive consumers tested positive for zopiclone at concentrations of 37 and 66 pg/mg. Hair analysis was applied to two authentic criminal cases. In the first one, zopiclone tested positive in the corresponding hair segment at 4.2 pg/mg, in accordance with a single exposure to the drug. In the other expertise, zopiclone was detected in the two segments analyzed, at 21.3 and 21.5 pg/mg, making unlikely the hypothetical single exposure to zopiclone.

The purported lowering of sex opposition, coupled with a possible abrupt unconsciousness-inducing effect and ease of administration in spiked drinks have resulted in the use of hypnotics in cases of drug-facilitated offense. Among these compounds, lorazepam possesses amnesic properties and can impair an individual rapidly. The chances to detect this substance increase if the most sensitive methods are used and if the biological fluid which allows the longest possible detection time is available. In order to document the window of detection of lorazepam, we have orally administered 2.5 mg of the drug to three volunteers and collected oral fluid (n = l) over 8 h, urine (n = 2) over 144 h and hair (n = 3) 4 weeks after exposure. Lorazepam was analyzed by LC-MS/MS after alkalinisation (to pH 8.4 with phosphate buffer) and extraction by dichloromethane/diethyl ether in presence of diazepam-d5, used as internal standard. Reversed-phase separation on a XTerra C18 column was achieved in 12 min, under gradient conditions. Molecular ions (m/z 321 and 290 for lorazepam and the IS, respectively) were selected in Ql and the corresponding daughter ions (m/z 303 and 275 for lorazepam and m/z 154 and 198 for the IS) were detected in Q3 after collision with argon. Urine tested positive for lorazepam over 144 h (2-4 ng/ml), with a peak detected after 24 h exposure (411-880 ng/ml). Oral fluid tested positive for lorazepam over 8 h (0.7 ng/ml). Despite a limit of quantitation at 1 pg/mg, we were unable to detect a single lorazepam dose in hair, contrarily to most other benzodiazepines that are detectable. Therefore, in case of drug-facilitated crimes involving lorazepam, urine appears as the best specimen to document exposure, particularly if LC-MS/MS is used.

The number of reports on drug facilitated crimes is increasing these last years. Apart from ethanol and cannabis, benzodiazepines (BZD) and analogs are the most common drugs reported to be used probably due to their amnesic and sedative properties. We have developed a rapid and sensitive method using LC-MS/MS triple stage quadrupole (TSQ) for the determination of single exposure to bromazepam (Lexomil, 6 mg) and clonazepam (Rivotril, 2 mg) in urine and hair of healthy volunteers. Chromatography was carried out on a Uptisphere ODB 5 microm, 2.1 mm x 150 mm column (Interchim) with a gradient of acetonitrile and formate 2 mM buffer, pH 3. Urine was extracted with Toxitube A (Varian) and allowed the detection of bromazepam, 3-hydroxy-bromazepam, clonazepam and 7-Aminoclonazepam for more than 6 days. Head hair, collected 1 month after the exposure, was treated by incubation with Soerensen buffer pH 7.6, followed by liquid-liquid extraction with dichloromethane for common BZD. A specific pre-treatment for amino-BZD, with an incubation of 15 min at 95 degrees C in 0.1 N NaOH before liquid-liquid extraction with dichloromethane, gave better recoveries and repeatability. After single exposure, bromazepam was present in powdered hair at 28 pg/mg and 7-Aminoclonazepam at 22 pg/mg in the first 1-cm segment, while no clonazepam was detectable. This method was applied in two forensic cases. It allowed us to determine bromazepam in urine 3 days after the alleged offense and in cut head hair at a concentration of 6.7 pg/mg only in the 2-cm proximal segment. The other case showed the presence of clonazepam and 7-Aminoclonazepam in urine a few hours after the offense and the presence of 7-Aminoclonazepam at about 3.2 pg/mg in axillary hair 4 months later.

Since gamma-hydroxybutyrate (GHB) is present in both blood and urine of the general population as an endogenous compound, toxicologists must be able to discriminate between these endogenous levels and a concentration resulting from exogenous exposure. The implementation of a cut-off concentration must be done cautiously, due to the wide distribution of endogenous concentrations. To verify the accuracy of a proposed 50 mg/l postmortem blood cut-off, we tested 71 autopsy cases of subjects where the cause of death could exclude GHB exposure. The delay between death and autopsy ranged from 12 to 72 h. GHB was tested by gas chromatography-mass spectrometry (GC-MS) after precipitation. Briefly, 20 microl of blood, bile, or vitreous humor was pipetted in a glass tube, followed by 20 microl of GHB-d6 and 45 microl of acetonitrile. After vortexing and centrifugation, the supernatant was collected and evaporated to dryness. The residue was derivatized with bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS) for 20 min at 70 degrees C. After injection on a 30 m HP5 MS capillary column, GHB (m/z 233, 204, and 147) and GHB-d6 (m/z 239) were identified by MS. GHB tested positive in all the 71 whole blood (cardiac) specimens, with concentrations in the range 0.4-409 mg/l, with a major distribution in the range 10-40 mg/l. A concentration >50 mg/l was observed in 14 cases. As there was no data to support GHB exposure, this was considered as postmortem formation. In order to discriminate this contamination, when available, femoral blood, bile or/and, vitreous humor were tested. The following results were obtained: cardiac blood (55-409 mg/l) versus bile (6.1-238 mg/l) in seven cases; cardiac blood (51-409 mg/l) versus femoral blood (17-44 mg/l) in five cases, and cardiac blood (51-409 mg/l) versus vitreous humor (3.9-2 mg/l) in six cases. It is obvious that bile does not fit the requirements for discrimination and that femoral blood and mostly vitreous humor can be of particular interest. These results demonstrate that a positive (>50 mg/l) postmortem blood GHB concentration cannot support alone drug exposure and that it is essential to document the case with other specimens, including peripheral blood and vitreous humor.

A solid-phase enzyme immunoassay involving microtiter plates was recently proposed by International Diagnostic Systems corporation (IDS) to screen for buprenorphine in human serum. The performance of the kit led us to investigate its applicability in other biological matrices such as urine or blood, and also hair specimens. Low concentrations of buprenorphine were detected with the ELISA test and confirmed by HPLC/MS (buprenorphine concentrations measured by HPLC/MS: 0.3 ng/mL in urine, 0.2 ng/mL in blood, and 40 pg/mg in hair). The intra-assay precision values were 8.7% at 1 ng/mL of urine (n = 8), 11.5% at 2 ng/mL in serum (n = 8), and 11.5% at 250 pg/mg of hair (n = 8), respectively. The immunoassay had no cross-reactivity with dihydrocodeine, ethylmorphine, 6-monoacetylmorphine, pholcodine, propoxyphene, dextromoramide, dextrometorphan at 1 and 10 mg/L, or codeine, morphine, methadone, and its metabolite EDDP. A 1% cross-reactivity was measured for a norbuprenorphine concentration of 50 ng/mL. Finally, the immunoassay was validated by comparing authentic specimens results with those of a validated HPLC/MS method. From the 136 urine samples tested, 93 were positive (68.4%) after the ELISA screening test (cutoff: 0.5 ng/mL) and confirmed by HPLC/MS (buprenorphine concentrations: 0.3-2036 ng/mL). From the 108 blood or serum samples screened, 27 were positive (25%) after the ELISA test with a cutoff value of 0.5 ng/mL (buprenorphine concentrations: 0.2-13.3 ng/mL). Eighteen hair specimens were positive (72%) after the screening (cutoff: 10 pg/mg) and confirmed by LC/MS (buprenorphine concentrations: 40-360 pg/mg). The ELISA method produced false positive results in less than 21% of the cases, but no false negative results were observed with the immunological test. Four potential adulterants (hypochloride 50 mL/L, sodium nitrite 50 g/L, liquid soap 50 mL/L, and sodium chloride 50 g/L) that were added to 10 positive urine specimens (buprenorphine concentrations in the range 5.3-15.6 ng/mL), did not cause a false negative response by the immunoassay.

Morphological, serological and chemical examination of human hair for medical purposes was initiated some decades ago. In the 1960s and 1970s, hair analysis was used to evaluate exposure to toxic heavy metals. At this time, examination of hair for organic substances, especially drugs, was not possible because analytical methods were not sensitive enough. Since the early 1980s, the development of highly sensitive and specific assay methods such as radioimmunoassay or gas chromatography/mass spectrometry has permitted the analysis of organic substances trapped in hair. This, theoretically, offered the possibility of revealing an individual's recent history of drug exposure beginning at sampling day and dating back over a period of weeks or months. The present review aims to summarise the various applications that have been published.