The present invention relates to plant extracts, specifically, the extracts of Chinese medicine Chenopodium ambrosioides L. and the composition comprising thereof. The extracts of Chinese medicine Chenopodium ambrosioides L. are prepared by conventional methods for the extraction of volatile oil, and can be used to treat Helicobacter Pylori-induced diseases of digestive system, such as gastritis, gastric ulcer, etc., with easy availability of raw materials, simple preparations, prominent effects, and less side-effect.