Opuntia species (Cactaceae) are a well known and important plant widely used in several indigenous system of medicine for the treatment of various ailments, viz. asthma, inflammatory diseases, ulcer and diabetes. Betalains and phenolic compounds have been reported as the major phytoconstituents of this species. The various analytical methodologies were used for the analysis of betalains in Opuntia species. Different pharmacological experiments in a number of in vitro and in vivo models have convincingly demonstrated the ability of Opuntia species to exhibit various pharmacological activities, leading support to the rational behind several of its traditional uses. Due to remarkable biological activity of Opuntia and its constituents, it will be appropriate to develop them as a medicine. The review summarizes a comprehensive knowledge on phytochemical compositions, analysis of betalains and ethnopharmacological actions of Opuntia species.