Naltrexone (NTX), an opioid antagonist, blocks intrinsic properties of substances that act on the mu, kappa and delta opioid receptor sites by competitive occupation. It is ascertained that alcohol acts on the opioid receptor sites. By blocking these sites, NTX prevents the reinforcing effects of alcohol consumption. Recent reviews of the effectiveness of NTX in the treatment of alcohol dependence agree that: a) NTX is effective in the treatment of alcohol dependence, especially with regard to the primary outcome parameter, i.e. relapse into heavy or uncontrolled drinking; b) NTX compliance probably is pivotal for successful alcohol treatment; c) There is some evidence that the combination of NTX and CBT (cognitive-behavioural oriented program) is somewhat more effective than NTX combined with supportive therapy; d) Also, there is some evidence that NTX can be of benefit to subgroups of alcoholics characterized by dual diagnosis, Type-II alcoholism or subjects with low level of clinical depression and alcohol dependence severity. Several strategies and hypothesis have been brought up in the literature, in which NTX compliance is subject of debate. Results of a current research about strategies to improve the effectiveness of NTX suggest that interventions aimed at enhancing medication adherence were more efficacy than strategies to increase the likelihood of taking NTX (“pill-count”).