Morphine produces contraction of Oddis 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 femalewho 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 resonancecholangiography showed normal fine bile duct, without stones. This transient increase in hepatic enzymes was considered as a consequence of high biliary pressuresecondary to morphine-induced spastic contraction of Oddis sphincter and a consecutive hepatocellular necrosis.