<p>Non-occlusive mesenteric ischemia (NOMI) is an acute form of intestinal ischemia that occurs in the absence of organic stenosis of the mesenteric arteries. Vasoconstrictive agents have been recognized as potential etiological factors. This report describes the first documented Japanese autopsy case of NOMI induced by methamphetamine (MA), a potent sympathomimetic agent.&#xa0;A forensic autopsy was performed on a man in his 60s who died suddenly. Gross and histopathological findings of the small intestine and mesenteric arteries were examined, and post-mortem toxicological analysis was performed to quantify the blood MA concentration.&#xa0;Autopsy revealed a dilated small intestine without mechanical obstruction, accompanied by non-contiguous ischemic necrosis and no signs of organic stenosis in the mesenteric arteries. Histopathological examination of the small intestine showed hemorrhage and necrosis, consistent with a diagnosis of NOMI. The blood concentration of MA was within the toxic range but below the fatal threshold, suggesting a causal relationship between MA use and the onset of NOMI. Given the fatal outcome despite an MA concentration below the reported fatal range, prolonged mucosal exposure from oral ingestion may have locally intensified vasoconstrictive effects, contributing to intestinal ischemia.&#xa0;This case highlights the importance of considering MA-induced NOMI in the differential diagnosis of sudden death among MA users and highlights the risk of fatal ischemic complications even at non-fatal MA concentrations.</p>