The possible interaction between cetirizine 2 HCl and alcohol was studied in a double-blind, cross-over trial in 36 healthy volunteers. The performance of each volunteer was tested with a battery of five objective psychometric tests, and their subjective feelings were evaluated by visual analogue scales, and by extensive questionnaire. The psychomotor performance and subjective inventory of health was significantly impaired by alcohol intake. Cetirizine 2 HCl was not different from placebo. There was no adverse interaction between cetirizine 2 HCl and alcohol. Cetirizine and alcohol did not modify each others blood levels.