Morphine produces contraction of Oddi’s sphincter, which can be severe and of longer duration in some pathological conditions. This exaggerated response can manifest as a colicky biliary pain, frequently accompanied by a dramatic increase in hepatic enzymes. We report a 32 years old female who consulted in the emergency room for severe low abdominal pain of gynecologic origin, which was completely controlled by morphine. However, she presented a sudden epigastric colicky pain irradiating in the back, which persisted for several hours in spite of the repeated administration of analgesics. Transaminases elevated from previously normal value to over 1,000 U/L, and returned to the normal level without further treatment after several days. Magnetic resonance cholangiography showed normal fine bile duct, without stones. This transient increase in hepatic enzymes was considered as a consequence of high biliary pressure secondary to morphine-induced spastic contraction of Oddi’s sphincter and a consecutive hepatocellular necrosis.