Abstract 10.1002/zoo.1430120509.abs This note reports on the use of gentamicin sulfate as a supportive measure for a juvenile blacktip reef shark (Carcharhinus melanopterus), which presented with an abrupt onset of anorexia, and laceration and prolapse of the scroll valve intestine (putative intestinal biting syndrome). Gentamicin sulfate was administered as an intramuscular injection (3.3 mg/kg body weight) every fifth day for seven treatments. The shark resumed feeding by 48 hours from the first injection, and was fully recovered by day 36. © 1993 Wiley-Liss, Inc.