OBJECTIVE: To probe into the effects of Paracetamol, caffeine, bovis calculus sativus and chlorphenamine maleate capsules ( Ankahuangmin capsules) on blood concentration of clozapine in patients with mental disorder during cold. METHODS: Medical records of 44 inpatients with mental disorders who underwent stable treatment with clozapine and took Paracetamol, caffeine, bovis calculus sativus and chlorphenamine maleate capsules (Ankahuangmin capsules) during cold from Jan. 2020 to Oct. 2021 in the hospital were retrospectively collected to obtain information on patients’ gender, age, dosing regimen, drug combination and blood concentration of clozapine, and statistical analysis was performed by using SPSS 25. 0. RESULTS: The blood concentration of clozapine increased to different degrees in 44 patients treated with Paracetamol, caffeine, bovis calculus sativus and chlorphenamine maleate capsules (Ankahuangmin capsules), the mean blood concentration was (444. 23±289. 24) ng / mL at baseline period and (621. 43±375. 23) ng / mL at intervention period; the white blood cell count (WBC) also increased to different degrees, the median value of WBC was 6. 67×109 / L at baseline period and 8. 06×109 / L at cold period; 12 patients experienced adverse drug reactions after blood concentration elevation of clozapine. CONCLUSIONS: The application of Paracetamol, caffeine, bovis calculus sativus and chlorphenamine maleate capsules (Ankahuangmin capsules) during the cold period has an effect on blood concentration elevation of clozapine, while the elevation of WBC could not significantly affect the blood concentration of clozapine. The monitoring on blood concentration of clozapine after drug combination of Paracetamol, caffeine, bovis calculus sativus and chlorphenamine maleate capsules ( Ankahuangmin capsules) and clozapine is crucial to avoid adverse drug reactions related to blood concentration of clozapine. [ABSTRACT FROM AUTHOR]