Objective: Aganosma dichotoma K. Schum (Apocynaceae) has been traditionally used as an Ayurvedic ulcer treatment and the study scientifically validates the antiulcer effect of A. dichotoma ethanol root extract (EAD).Methods: The studies included the isolation, quantification of ursolic acid through HPTLC. Acute and sub-acute toxicity study of EAD for 28 d and antiulcer effect of ursolic acid (50 mg/kg, p. o.), EAD (100, 200 and 400 mg/kg, p. o.) were also evaluated on both the physical (pyloric ligation, PL; cold restrain stress, CRS;) and chemical (absolute ethanol, aspirin, ASP;) induced ulcer in Charles Foster albino rats for 7 d. The various gastric-ulcer parameters, viz. gastric pH, volume, acid-pepsin output, DNA content, H+K+-ATPase activity, mucus content, microvascular permeability, antioxidant enzyme, and gastric histopathological study were performed.Results: The isolated ursolic acid was characterized by NMR and mass spectrometer and quantified through HPTLC in EAD (4.26% w/w). Acute oral toxicity study indicated that LD50 of extract was ≥ 5 g/kg. EAD at the dose of 200 and 400 mg/kg, p. o. reduced the ulcer score in both physical and chemical-induced ulcer models. In PL model EAD (400 mg/kg, p. o.) and ursolic acid (50 mg/kg, p. o.) showed antisecretory property by inhibiting aggressive factors [increase in gastric pH (35.02%, 26.73%), whereas decreased gastric volume (43.55%, 34.35%) and acid-pepsin output (75.23%, 68.81%), respectively]. EAD at 400 mg/kg p. o. showed significant effect on proton pump inhibition while ursolic acid didn't showed any effect.Conclusion: The effects of EAD were accredited mainly to the offensive mechanism and justify its traditional usage in the treatment of gastric ulcers
