Linn. (Araceae), commonly known as "sweet flag" or "calamus", is a semiaquatic, perennial, aromatic herb with creeping rhizomes. The plant is found in the northern temperate and subtropical regions of Asia, North America, and Europe. The plant exhibits polyploidy. Many ethnomedicinal and ethnobotanical uses have been ascribed to the rhizomes of the plant. A. calamus. Linn. (AC) has been used as traditional Chinese and Indian prescriptions for its beneficial effects on memory disorder, learning performance, lipid peroxide content, and anti-aging and anticholinergic activity. Moreover, pharmacological studies have revealed that Acorus. rhizome and its constituents, particularly +.- and .-asarone, possess a wide range of pharmacological activities such as sedative, CNS depressant, behavior modifying, anticonvulsant, acetylcholinesterase inhibitory, memory enhancing, anti-inflammatory, antioxidant, antispasmodic, cardiovascular, hypolipidemic, immunosuppressive, cytoprotective, antidiarrheal, antimicrobial, anthelmintic, insecticidal, adulticidal, diuretic, antioxidant, genotoxic, and mutagenic activities. This review is an effort to explore the different phytoconstituents and pharmacological activities of Acorus calamus..