Narasin is a coccidiostat and antibacterial agent. It is a derivative of salinomycin with an additional methyl group. Narasin is produced by fermentation of a strain of Streptomyces aureofaciens.Narasin is authorized as a coccidiostat feed additive for the control of Eimeria infection in chickens for fattening. Narasin, at the levels used for the treatment of coccidiosis, is also effective in the prevention of necrotic enteritis in chickens. The antimicrobial spectrum of narasin is mainly limited to Gram-positive bacteria, including enterococci, staphylococci, and C. perfringens.