The aim of the study was to evaluate the comparative effectiveness of Glycyrrhiza glabra (liquorice) root decoction vs. omeprazole and misoprostol for the treatment of aspirin-induced gastric ulcers in rats. Animals were randomly assigned first to the "prophylaxis" and "treatment" groups and then to the test and the control groups. Liquorice decoction (25 ml/kg; i.g.); omeprazole (2.3 mg/kg; i.p.) and misoprostol (50 mu g/kg; i.g.) were administered for 3 consecutive days 30 min before aspirin (200 mg/kg, i.g.) administration, in the prophylaxis group. In the treatment group, aspirin (200 mg/kg, i.g.) was administered for 3 consecutive days, and then other drugs were administered at the same doses as the prophylaxis group daily for 4 weeks. According to histopathologic evaluation, misoprostol showed significant protection; however, liquorice decoction and omeprazole failed to protect. In the treatment group histopathological examinations showed no significant difference among liquorice decoction, misoprostol and omeprazole regarding aspirin-induced ulcer treatment; ulcers in all treatment groups were completely cured. The results of this study suggest that Glycyrrhiza glabra can be used for the treatment of NSAID-induced ulcers as an inexpensive alternative to misoprostol and omeprazole.