Gastritis and gastric ulcer were known to be induced by gastic acid, stress, ethanol, Helicobacter pylori and free radical, etc. This study was performed for the development of a new drug or nutraceutical from medicinal plants or natural products with anti-gastritis, anti-ulcerative and gastroprotective activities. The water extract of Scutellaria baicalensis was exhibited potent inhibition in HCl ethanol-induced gastric lesion, acetic acid-induced and Shay ulcers, indicating the effects on gastric lesion and ulcer in rats. The water extract of Scutellaria baicalensis significantly inhibited HCl ethanol-induced gastric lesions at the oral dose of 300, 500 mg/kg. In pylorus ligated rats, the treatments of the water extract from Scutellaria baicalensis showed decrease in the volume of gastric secretion and acid output and increase pH at oral dose of 300, 500 mg/kg. And significantly reduced acetic acid-induced ulcer at the oral dose of 500 mg/kg for 12 days. In this study, we have found that the water extract from Scutellaria baicalensis had significant improvement in acute gastritis and ulcer at the dose of 300, 500 mg/kg and in chronic gastritis and ulcer at the dose of 500 mg/kg. Also we evaluated the antibacterial activity against Helicobacter pylori treated with Scutellaria baicalensis. Scutellaria baicalensis had a equivalent antibacterial activity with ampicilin against H. pylori at the dose of $100;{mu}/ml$. In histological examination, the water extract of Scutellaria baicalensis drastically restored gastric damages induced by HCl ethanol solution, pylorus- ligature and acetic acid. Therefore, we may use the water extract from Scutellaria baicalensis as antigastritic and antiulcerative agent for the purpose of the improvement or treatment of gastritis and gastric ulcer.