A 78-year-old man underwent biliary stenting by means of endoscopy for obstructive jaundice due to common bile duct cancer. Despite uneventful operation, the patient remained comatose and began to hiccup and vomit with marked gastrointestinal gas retention. Neuroimaging studies disclosed obstructive hydrocephalus caused by a midbrain metastasis, probably from coexisting lung cancer. Ventricular peritoneal shunting restored consciousness and eliminated other gastrointestinal symptoms. This case suggests that gastrointestinal endoscopy may affect concurrent intracranial lesions, resulting in acute distress, presumably by transmission of pressure from the abdomen to a distant body compartment such as the intracranial space, or by endoscopy-related hypoventilation.