2,6-DIMETHOXYPHENYL penicillin monohydrate is a new synthetic penicillin said to be effective in vitro against a variety of gram-positive bacteria, including hemolytic staphylococci resistant to penicillin G.1 The present report deals with the in vitro antimicrobial activity of dimethoxyphenyl penicillin in comparison to penicillin G against 100 isolates of staphylococci from clinical sources and its efficacy in the treatment of 41 patients with surgical infections due largely to staphylococci. This series includes 31 patients who had failed to respond to other antibiotics and 10 others treated only with dimethoxyphenyl penicillin.In Vitro StudiesOne hundred clinical isolates¶ of staphylococci, most . . .