The volatile oil of Boswellia serrata. Roxb ., showed significant antiulcer activity in albino rats by pyloric ligationmodel. The albino rats of either sex were divided in to three groups the animals were deprived of food for 24 hours before the commencement of experiment. The drugs were given intraperitoneally . The animals were sacrificed 6 hours after pylori ligation to observe gastric lesion. The gastric juice was collected and its pH determined titrimetrically by using 0.01N sodium hydroxide solution. The acid secretion and after index were analyzed by student ÂtÂ test. It showed significant antiulcer activity. The extract reduces the gastric activity and ulceration by histaminergic mechanism by H2 receptor blockade.