Expts. were undertaken to determine whether or not sulfanilamide and azoehloramid act synergistically in vivo against Group A hemolytic streptococci in artificial wounds of rabbits. Sulfanilamide, sulfadiazine, and sulfathiazole either caused only a slight decrease in the number of hemolytic streptococci or were ineffective. Azoehloramid, in conc. from 0.26 to 1.3%, was markedly effective. No evidence was obtained that sulfanilamide and azochloramid act synergistically in vivo toward this Group A streptococcus in artificial wounds of rabbits.