Sheep sorrel is a flowering plant considered a perennial weed. It is native to Europe, Russia, and the Middle East and North Africa, and is prevalent in the United States. Historically used to treat inflammation, scurvy, cancer, and diarrhea, sheep sorrel is also one of four ingredients in Essiac, an alternative cancer treatment.
Scientific research has not been conducted on sheep sorrel, but there is familiarity with how some of the compounds in this plant work. Anthraquinones might produce a laxative effect by stimulating movement in the GI tract and increasing fluid levels in the intestines. These compounds are also considered antioxidants that may be able to neutralize free radicals, which can cause cellular and DNA damage in the body.