Abstract: Intracerebroventricularly (I.c.v.) administered GABA (2.4.6 umol) significantly accelerated the development of gastric ulcer induced by ethanol (o.p.) in mice in a dose dependent manner,whereas GABA (I.p.100 umol) could not modify the ethanol-induced ulcer in mice.Atropine (s.e.0.2 mg/kg) exacerbated the ethanol-induced ulcer significantly,while blocking the exacerbation of ulcer induced by GABA partly.Regetine (I.m.2.5 mg/kg) potentiated the ethanol-induced ulcer weakly,and had no effect on the exacerbation of ulcer induced by GABA.These results suggested that exsragenetic GABA exacerbates the ethanolinduced gastric ulcer through central GABA-ergic mechanisms,but not peripherally.Vagus may contribute to gastric protective effect against ulceration.It may be one of main pathway in GABA s action.Sympathetic nerve maybe have relationship with the GABA-ergic mechanisms.