Cassiae semen (Leguminosae), a well-known traditional Chinese medicine, has been used for a number of centuries in areas of Southeast Asia, including Korea, Japan and China. The present review aims to provide updated and comprehensive information, on the botany, phytochemistry and pharmacology of Cassiae semen. The available information on Cassiae semen was collected using several different resources, including classic books on Chinese herbal medicine and a number of scientific databases, including the China Academic Journals full-text database, PubMed, SciFinder, the Web of Science and Science Direct. To date >70 chemical compounds have been isolated from Cassiae semen, and the major components have been determined to be anthraquinones, naphthopyrones and volatile oil. The crude extracts and pure compounds of Cassiae semen have been used as effective agents in preclinical and clinical practice due to their beneficial activities, including antihyperlipidemic, antidiabetic, neuroprotective, hepatoprotective, antibacterial, antioxidant and hypotensive activities. With the body of reported data, it has been suggested that Cassiae semen has convincing medicinal potential. However, the pharmacological mechanisms of the main bioactive compounds and the association between structure and activity require further investigation.