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 anti-ulcer 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 IC(50) of 77 microg/mL as opposed to that of 19.3 microg/mL of Lansoprazole and H pylori growth at Minimum Inhibitory Concentration (MIC) of 150 microg/mL. In addition, free radical scavenging (IC(50)-40 microg/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.