A complex mixture of related natural products isolated from the fermentation broth of a strain of Actinoplanes teichomyceticus comprising five major components (teicoplanin A2-1 through A2-5), a hydrolysis component (teicoplanin A3-1), and four minor components (teicoplanin RS-1 through RS-4). An antibiotic with a similar spectrum of activity to vancomycin, it is used to treat serious Gram-positive bacterial infections, including methicillin-resistant Staphylococcus aureus and Enterococcus faecalis.