Baclofen is a lipophilic analogue of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in central nervous system. The aim of the study was to evaluate some clinical aspects of acute intoxication with baclofen. Fifty two patients (37 females and 15 males) aged from 14 to 58 (mean 30.6 +/- 13.7) years were analyzed. Patients were admitted to the Clinic of Internal Diseases and Acute Poisonings Medical University of Gdańsk and the Centre of Acute Poisonings of Praski Hospital in Warszawa during the years 1996-2004 because of suicidal intoxication with baclofen. The doses of baclofen varied from 100 to 1500 (mean 444.8 +/- 317.8) mg. There were twenty eight patients (53.8%) in deep coma (III and IV grade of Matthew scale). Acute respiratory failure which required mechanical ventilation was observed in 18 cases (34.6%). Cardiac abnormalities included bradycardia (36.5%), hypertension (32.7%) and hypotension (3.8%). Toxic psychoses were observed in 6 cases (11.5%). The dosage of baclofen in patients with acute respiratory failure (ARF) was significantly higher than in patients without ARF. Treatment of patients with acute baclofen intoxication should take place in hospitals appropriately equipped which can provide artificial respiration.