A 50-year-old woman with acute onset of right lower quadrant pain and hematochezia proved to have segmental ischemic colitis associated with methamphetamine abuse. The diagnosis was established by colonoscopy with biopsy, and abdominal angiography revealed no thrombosis, vasculitis, or vasospasm. The condition resolved within 10 days. Since methamphetamine abuse is increasing, physicians should be aware of its potential to produce intestinal ischemia.