Clinically relevant, recent isolates of common Gram-positive pathogens were examined for their in vitro susceptibility to cefaclor. Group A streptococci and pneumococci were uniformly sensitive (MICs 0.06--0.12 micrograms/ml) to both cefaclor and cephalothin. Cefaclor was 5--10-fold less active than cephalothin against group B streptococci. S. aureus strains were uniformly more susceptible to cephalothin than to cefaclor, but among isolates from children, almost all were sensitive to the latter drug. In clinical studies of patients with skin and soft tissue infections, cefaclor proved effective. Over 90% of patients with staphylococcal bullous impetigo, streptococcal and mixed streptococcal-staphylococcal forms of pyoderma were cleared after 7--10 day courses of treatment. In addition, twice-daily therapy, examined more recently, proved as effective in these forms of infection as did the conventional dose schedule. No significant adverse reactions were noted. Cefaclor appears to be an effective orally absorbed cephalosporin for common skin and soft tissue infections.