&NA;Intron A (Interferon‐&agr;‐2b Recombinant) for injection, a product by Schering‐Plough Corporation, is a recombinant DNA, genetically engineered copy of a naturally occurring protein which acts as an antiviral agent. This product is now approved in the United States for the treatment of chronic non‐A, non‐B hepatitis, also known as hepatitis C. Intron A represents an important advance in the treatment of chronic hepatitis non‐A, non‐B/C because until now, although many other drugs have been tried, there has been no effective treatment.