Few studies have evaluated the relationship between drugs of abuse consumption and plasma levels of vitamin C. Because of the importance of vitamin C due to its role in prevention of acute and chronic diseases, this study was carried out with the purpose of testing the influence of consumption of drugs of abuse on the plasmatic levels of vitamin C (ascorbic acid) of 56 male chronic users of drugs of abuse with an age range of 16 to 40 years. The following was performed: 1) A survey of consumption to determine the kind, frequency and quantity of drug(s) used and 2) The plasmatic levels of vitamin C in fasting condition, using the Rue and Kuether method. The results obtained showed that 89% of the population under study used drugs for the first time before the age of 18, and 78.4% started with marijuana; 60.7% of them were mixed drug users. The average level of plasmatic ascorbic acid was 0.89 +/- 0.06 mg/dL, nevertheless, according to nutritional category, 76% have values greater than 0.4 mg/dL and 23.2% were at moderated risk (0.35 +/- 0.01 mg/dL) of vitamin C deficiency. Likewise, classifying them in the antioxidant category (according to the suggested values of Gey, 1993) it was obtained that 55.4% had suboptimal or inadequate concentrations to carry out its antioxidant protective function. The length of time of drug's consumption influenced on the ascorbic acid level too. It can be concluded that chronic consumption of drugs of abuse can negatively influence the plasmatic levels of ascorbic acid, leading these patients to a latent condition of vitamin C deficiency. Finally it is necessary to deepen the study of vitamin C levels of users of drugs of abuse.