One of the most potent agents against non-spore forming anaerobic bacteria, the Bacteroides spp. CAUSES severe diarrhea and PSEUDOMEMBRANEOUS COLITIS (reversible) Its use SHOULD BE RESERVED for staph tissue infections, such as cellulitis and osteomyelitis, pen-allergic pts, severe anaerobic infections outside CNS Replacement of 7(R)-hydroxy group of lincomycin with chlorine 7(S)-chloro-7-deoxylincomycin (Cleocin)