Use of clindamycin and lincomycin in St. Thomas' Hospital appears to parallel that in many other hospitals in the United Kingdom. Both drugs were accepted at first cautiously then with enthusiasm, clindamycin replaced lincomycin as its improved in vitro and pharmacological properties were recognized and the anaerobic renaissance of the 1970s resulted in the widespread use of clindamycin in particular for infections with Gram-positive organisms and anaerobes. The association of pseudomembranous colitis with the use of clindamycin in about 1973 resulted in a decline in the use of the two drugs and this further declined when metronidazole became available as a highly effective alternative to clindamycin for the treatment and prevention of serious anaerobic infection. In a phase of over-reaction no clindamycin or lincomycin was used for a period of about 2 years. During this time the aetiology of pseudomembranous colitis was determined and an effective therapeutic approach worked out. A number of clinicians remembering the effectiveness of clindamycin in a variety of infections re-introduced it despite the CSM warnings that its use be reserved for severe infection. The final rational level of usage remains to be determined but it is clear that clindamycin if not lincomycin has a rational place in the antibiotic armamentarium.