Nonsuppurative peripheral thrombophlebitis is a frequently recognized source of sepsis. Eleven patients cared for on general medical and surgical services had Gram-negative bacillary sepsis on this basis. Ten had isolation of organisms of the Klebsiella-Enterobacter group from the involved peripheral vein. All failed to respond to organism-sensitive antibiotics until the involved vein was excised. After local vein excision, all patients were afebrile within 48 hours and recovered. In seven of the 11 patients, the septic phlebitis source was associated with a standard intravenous needle, and none had cutdown procedures. It is strongly emphasized that this condition is a source of life-threatening sepsis that can be treated by vein excision at the bedside. The treatment in our patients resulted in no morbidity. A high index of suspicion is necessary to diagnose this occult source of sepsis because of the minimal local physical signs.