AIM: To investigate H+, K+-ATPase inhibition,anti-H pylori, antioxidant, and the in vivo antiulcer potential of a pectic polysaccharide from Swallow root (Decalepis hamiltonii; SRPP).METHODS: SRPP, with known sugar composition[rhamnose: arabinose: xylose: galactose in the ratio of 16:50:2:32 (w/w), with 141 mg/g of uronic acid] was examined for anti-ulcer potency in vivo against swim/ethanol stress-induction in animal models. Ulcer index,antioxidant/antioxidant enzymes, H+, K+-ATPase and gastric mucin levels were determined to assess the antiulcer potency. Anti-H pylori activity was also determined by viable colony count and electron microscopic studies.RESULTS: SRPP, containing phenolics at 0.12 g GAE/g,prevented stress-induced gastric ulcers in animal models by 80%-85%. Down regulation of gastric mucin 2-3 fold, antioxidant/antioxidant enzymes and upregulation of 3 fold of H+, K+-ATPase in ulcerous animals were normalized upon treatment with SRPP. Histopathological analysis revealed protection to the disrupted gastric mucosal layer and epithelial glands. SRPP also inhibited H+, K+-ATPase in vitro, at an IC50 of 77 μg/mL as opposed to that of 19.3 μg/mL of Lansoprazole and H pylori growth at Minimum Inhibitory Concentration (MIC) of 150 μg/mL. In addition, free radical scavenging (IC50-40 μg/mL) and reducing power (3200 U/g) activities were also observed.CONCLUSION: SRPP, with defined sugar composition and phenolics, exhibited multi-potent free radical scavenging, antioxidant, anti-H pylori, inhibition of H+,K+-ATPase and gastric mucosal protective activities. In addition, SRPP is non-toxic as opposed to other known anti-ulcer drugs, and therefore may be employed as a potential alternative for ulcer management.