The newly synthesized, 3,4,5-Trihydroxy-N 0-[(2-methyl-1H-indol-3-yl)-methylidene] benzohydrazide (TIBH), is an indole and gallic acid derivative. The aim of this research investigation was to evaluate the acute toxicity and the ulcer prevention potential of TIBH in HCl/Ethanol-induced gastric ulcer rat model. Six groups of rats were orally received 5ml/kg of vehicle (1 % Carboxy methyl cellulose) for the normal and ulcer control groups each, Omeprazole (20mg/kg) for positive control, 50 mg/kg, 100 mg/kg and 200 mg/kg of TIBH for experimental groups, respectively. After one hour, instead of rats in the normal group which received 5ml/kg of 1% CMC, other groups received 5ml/kg of HCl/Ethanol. All rats were sacrificed after one additional hour. Gastric juice, gastric mucosa, morphologies of gastric ulcers and protein expressions of both control and treatment groups were evaluated. TIBH showed a ulcer prevention potential by increase of the mucus secretion, decrease of the gastric acidity, up-regulation of HSP70 protein, down-regulation of Bax protein, decrease of the lipid peroxidation and the increase of the Superoxide dismutase (SOD) activity in gastric tissue homogenate. Acute toxicity assay exposed valuable information on the safety of this compound. TIBH had a dose dependent ulcer prevention potential against HCl/Ethanol-triggered gastric ulcer.