Fractions of plasma proteins were marked in 135 alcohol dependent men. The increase in the level of beta globulins was found in 58%, a fall in the level of gamma globulins was found in 52% and in 26% of patients a fall in the level of albumin was recorded. Patients with a shorter period of dependence more frequently showed a lowering of the concentration of gamma globulin (59% of cases). Persons with a greater pathological pattern of dependence, however, showed an increase in the level of beta globulin (65% of cases). The joint use of beta globulin and gamma globulin as markers of alcohol abuse allowed for the detection of irregularities in the range of at least one of the above mentioned markers in 84% of the patients. The joint use of albumin, beta globulin and gamma globulin showed irregularities in at least one of these three tests in 90% of the patients. The authors conclude that marking the changes in the fraction of plasma proteins may be used as a biochemical marker of alcohol abuse.