Acorus calamus (Acoraceae), also known as Calamus or Sweet Flag is commonly used herbal medicine in Ayurvedic system. It is a semi aquatic herb growing in shallow water or in a very moist loamy soil. Roots and rhizomes of Acorus calamus have been used as a single drug or as a component of certain compound drug preparations in the Indian Ayurvedic system of medicine for psychoneurosis, insomnia, hysteria, epilepsy and loss of memory. It is also use in the treatment of cough, fever, bronchitis, inflammation, depression and other mental disorders, tumors, haemorrhoids, skin diseases, numbness and general debility. This review article has compiled all the information on its phytochemical and pharmacological activities. It contains volatile oil with active constituent as α-asarone and β-asarone. Its saponine contain is also identified. Various studies indicated that calamus possesses anticonvulsant, antioxidant, neuroprotective and immunomodulaory properties. Various other effects like anticellular, antibacterial and central muscle relaxant properties of calamus also been reported. It is also reported that some spesis of calamus possesses carcinogenicity. In the present review an attempt has been made to explore different ethanopharmacological aspect of Acorus calamus.