Cassia siamea Lamk is a tropical plant of family Caesalpiniaceae and is native of Southeast Asia. It is well-known for its nutritional, medicinal and economic importance and has been traditionally used for the treatment of ailments such as fever, malaria, diabetes, hypertension, asthma, constipation, diuresis, CNS disorders, jaundice, abdominal pain and menstrual pain either in crude form or as decoction of leaves and flowers. In some part of Asia, leaves and flowers of C. siamea are used as vegetables. Exhaustive literature is surveyed and summarized in this review to bring singlepot information for C. siamea available since 1925. C. siamea plant is found to be medicinally important for the treatment of several pathological complications. At the same time, it has also nutritional and economic importance. The major phytochemical constituents present include anthraquinones along with coumarins, alkaloids, flavonoids, glycosides, triterpenoids, sterols and other polyphenols. Further research on this plant has explored its specific pharmacological properties such as analgesic, antioxidant, anti-inflammatory, antimalarial, vasorelaxant, antitumor, antiarrhythmic, antiandrogen, anti-HIV and anxiolytic activity in various in vitro and in vivo studies. There is couple of reports that show toxicity concerns of this plant. It is an attempt to summarize morphological, microscopic, phytochemical, pharmacological and toxicological studies for improving research exploration and biomedical application potential of C. siamea.