Abstract: The present invention relates to a method of treating alcoholism or alcohol abuse by administering to a subject a pharmaceutically effective amount of an opioid antagonist before imminent drinking. Particularly, the present invention relates to a method of treating alcoholism or alcohol abuse by administering transmucosally to a subject a pharmaceutically effective amount of an opioid antagonist before imminent drinking. Preferably, the opioid antagonist used in the method is nalmefene or a pharmaceutically acceptable salt thereof. The invention also relates to a method of treating alcoholism or alcohol abuse by administering to a subject before imminent drinking a transmucosal preparation comprising a pharmaceutically effective amount of an opioid antagonist, wherein the transmucosal preparation has rapid onset of action. Advantageously, a FAH+ subject is treated.