Contains two streptogramin antibiotics, virginiamycin M1 (75%) and virginiamycin S1 (25%); irreversibly inhibits protein synthesis in bacteria; improves growth of livestock; used in fuel ethanol fermenters to prevent to control bacteria competing with yeast for nutrients.

Natural mixture of two cyclic lactone peptolides, factors M and S, produced by Streptomyces sp. Application: For Research and Laboratory use only