Cutaneous reactions to drugs are a common and important complication in medical practice where the dermatologist plays a key role. So far, in Medellin, Colombia, there are no studies or any publications about the behavior of drug eruptions. Objective: The clinical and epidemiologic characteristics of drug eruptions were described in hospitalized patients at the Hospital Pablo Tobón Uribe. Methods: An observational descriptive retro-prospective study was carried out in patients hospitalized in the Hospital Pablo Tobón Uribe who showed skin reactions to drugs in the period from January 1st, 2007, to November 15, 2009. Results: The study included 169 patients (52.7% male and 47.3% women). The age range of presentation of skin reactions to drugs were recorded from 8 months to 97 years old, with a mean of 38.5±24.7 years old. Antibiotics were responsible for more than half of the cases (54.4%), followed by analgesics (22.5%), anticonvulsants (8.9%) and others 8.9%. In 66.3% of patients, a single drug was identified as the causative agent. The most commonly encountered clinical patterns were macula-papular rash (76.3%) and urticaria (13.6%). The average body surface area involved was 47.07% ± 25.9. The most affected body area was the anterior chest in 76.3%, followed by the upper limbs in 70.4%, 68.6% lower limbs and back 60.9%. The face and neck were less affect, with 39.1% and 26%, respectively. Conclusion: This observational study showed a behavior of skin reactions to drugs in hospitalized patients of Hospital Pablo Tobón Uribe very similar to that reported in other countries supported by the clinical presentation type rash, most commonly in the thorax and limbs, and for being the most frequent causative agent antibiotics and analgesics. [ABSTRACT FROM AUTHOR]