The present paper reports 2 cases of methamphetamine abuse. Following consecutive methamphetamine administration, the patients developed acute intoxication, during which time they showed a unique type of disturbance of consciousness: delirium and twilight state. In both cases, mental status changed, passing through three distinct stages: restlessness and insomnia, hallucinatory paranoid state, and disturbance of consciousness. A review of the literature suggests that disturbance of consciousness may occur occasionally during the course of amphetamine and methamphetamine intoxication, although these symptoms can be overlooked easily due to confounding symptomatology.