Acorus calamus Linn. is a perennial herb, growing wild on the edges of swamps, banks of rivers and ponds in North America, Europe and India. It is an aromatic herb, used in various ailments like CNS depression, neurodegeneration, convulsion, inflammation and many more. This book emphasize on role of this herb in Rheumatoid Arthritis (RA), a leading cause of disability in elderly. RA is an autoimmune disorder, characterized by inflammation and pain in joints. It is incurable disease till date and treatment available is mainly symptomatic. Acorus calamus showed excellent preventive activity against RA and can be used as adjuvant in therapy.