Penicillin must not be used indiscriminately, but its effectiveness in combating susceptible infections is benefiting practically every branch of medicine. We have employed it at Bushnell General Hospital since April 1943 chiefly in overwhelming infections and complications of ear, nose and throat diseases when life was endangered. In the entire series of 19 cases the organisms were those which are sensitive to penicillin, in general the group of cocci. This presentation will be limited to the 9 cases classified as instances of sinus complications. Originally penicillin was administered intravenously, either by repeated venous punctures every two hours or by continuous drip, but both of these methods have largely been supplanted by the intramuscular route. Continuous drip injection may be preferable for extremely ill persons with grave infections when a high prolonged blood concentration is desired. After the hazardous phase has subsided, intramuscular use may be substituted. In general, the dosage