Potent extracts from rhizomes of Zingiber officinale may be used to treat a disease associated with Helicobacter pylori such as gastritis, gastric ulcer or duodenal ulcer. The potent product is prepared by a process including the steps of (a) preparing a crude extract from rhizomes of Zingiber officinale, said crude extract comprising 6-ginerol and 6-shogaol, (b) introducing the crude extract to a reverse phase chromatography column and eluting with a first eluent having a polarity that is lower that water to obtain a first potent fraction and then extracting with a second eluent that is lower in polarity than the first eluent, to obtain a second potent fraction. The second potent fraction is substantially free of both 6-ginerol and 6-shogaol. Elution may also be carried out on a normal phase chromatography column.
