Pimpinella anisum (anise), belonging to Umbelliferae family, is an aromatic plant which has been used In Iranian traditional medicine (especially its fruits) as carminative, aromatic, disinfectant, and galactagogue. Because the wide traditional usage of Pimpinella anisum for treatment of diseases, in this review published scientific reports about the composition and pharmacological properties of this plant were collected with electronic literature search of GoogleScholar, PubMed, Sciencedirect, Scopus, and SID from 1970 to 2011. So far, different studies were performed on aniseeds and various properties such as antimicrobial, antifungal, antiviral, antioxidant, muscle relaxant, analgesic and anticonvulsant activity as well as different effects on gastrointestinal system have been reported of aniseeds. It can also reduce morphine dependence and has beneficial effects on dysmenorrhea and menopausal hot flashes in women. In diabetic patients, aniseeds showed hypoglycemic and hypolipidemic effect and reduce lipid peroxidation. The most important compounds of aniseeds essential oil were trans-anetole, estragole, γ-hymachalen, para-anisaldehyde and methyl cavicol. Due to broad spectrum of pharmacological effects, and very few clinical studies of Pimpinella anisum, more clinical trials are recommended to evaluate the beneficial effects of this plant in human models and synthesis of new drugs from the active ingredients of this plant in future.