The authors evaluated whether depth of needle insertion as determined by needle length is an important factor in sclerotherapy-associated bacteremia. In 18 consecutive sclerotherapy sessions in which sodium morrhuate was used, blood cultures were positive in 11% when using an injector with only 3 to 4 mm of needle protruding beyond the sheath, compared with the 39% incidence of bacteremia previously observed when an injector was used which permitted 6 to 8 mm of needle to protrude (0.01 < p < 0.05). Twenty-five additional sclerotherapy sessions in which the shorter needle was used were performed with a different sclerosant, 1% sodium tetradecyl sulfate; only 8% of blood cultures were positive. No correlation was found between fever and bacteremia. The authors conclude that the exposed needle length of the injector must be specified in any report of endoscopic variceal sclerotherapy with the flexible endoscope since this length is critical in the incidence of associated bacteremia and possibly other complications.