Inclusion Criteria:

1. Forty men and women between the ages of 25 to 60 years meeting DSM-IV criteria for current alcohol dependence.
2. Subjects must either have been admitted to UNC Hospitals for a medical detoxification from alcohol and be receiving benzodiazepines for detoxification or recruited from the general population.
3. Must have had at least 2 heavy drinking days (≥5 drinks/day for men or ≥4 drinks/day for women) per week, on average and an average overall consumption of 21 drinks/week or more for men and 14 drinks/week or more for women during the 4 weeks prior to admission or screening and no more than three months of abstinence in the previous year.
4. Able to understand and sign written informed consent.
5. Willingness to engage in treatment and motivation to achieve abstinence or to greatly reduce alcohol consumption.
6. Must have a stable residence and be able to identify an individual who could locate subject if needed.
7. Must have the logistical ability to come to study visits.(This study is being conducted in Chapel Hill, NC. Therefore participants must be able to attend each clinic visit for 12 weeks.)

Exclusion Criteria:

1. Clinically significant medical disease that might interfere with the evaluation of the study medication or present a safety concern (e.g., cirrhosis, kidney impairment, unstable hypertension, hypotension, diabetes mellitus, seizure disorder).
2. Patients taking glucocorticoids or immunosuppressants.
3. Clinically significant psychiatric illness including any psychotic disorder, bipolar disorder, severe depression, persistent suicidal ideation or suicide attempt, or substance use dependence other than alcohol or nicotine.
4. Any prior history of, or currently presenting with, withdrawal seizure or delirium tremens.
5. AST, or ALT > 3 times Upper Limit of Normal (ULN), or bilirubin > ULN, or estimated glomerular filtration rate < 60.
6. Positive urine toxicology screen with the exception of cannabis or cocaine for inpatients only. Patients recruited from the general population who present with a positive urine toxicology screen other than cannabis will be excluded. Any subject with positive cannabis or cocaine screens will be excluded if they have a history of dependence.
7. Concurrent use of mood stabilizers, antipsychotics, stimulants, or hypnotics. Use of benzodiazepines is prohibited except during the withdrawal period for inpatients. Antidepressant medication is permitted.
8. Concurrent use of anticonvulsants, insulin, or oral hypoglycemics.
9. Concurrent use of opiates or any use of opiates within 7 days prior to Naltrexone use.
10. Participation in any clinical trial within the last 60 days.
11. Court-mandated participation in alcohol treatment or pending incarceration.
12. For inpatients, lack of urine toxicology or pregnancy test done on date of hospital admission. Outpatient subjects will have a urine toxicology screen and a pregnancy test done (if female).
13. If female, pregnant or breastfeeding women and women of child bearing potential who do not practice a medically acceptable form of birth control.