A new anti-infectious compound ("Bactrim", sulfatmethoxazole + trime- thoprim), with bactericidal effect upon Gram positive and Gram negative bactéria, was assayed in the treatment of 15 cases of salmonelosis and 9 cases of varied bactericil infections. Results were favourable both in salmonelosis and in infections produced by staphlococcus, shigela, pneumococcus and coliform bacilli. Remission of toxemia in typhoid fever ocurred within 48 hours, and fever and other symptoms disappeared before the third day of treatment. Side effects were observed in some patients, represented by hyperthermia, skin reaction. vomiting and lymphomonocyíosis and eosinophilia, possibly dose related and always disappearing with suspension of the treatmente or reduction of the posology. The authors are of the opinion that the new compound is a promissing therapy for typhoid fever and bacterial infections in a general way.