BACKGROUND This study aimed to evaluate the effects of alcohol intake, assessed using the Alcohol Use Disorder Identification Test (AUDIT) questionnaire, on the severity of plaque psoriasis using the Body Surface Area (BSA) and Psoriasis Area and Severity Index (PASI) scales, and quality of life using the Dermatology Life Quality Index (DLQI) questionnaire. MATERIAL AND METHODS The diagnosis of psoriasis was made based on the clinical picture. We enrolled 24 patients with psoriasis vulgaris, and the AUDIT test conducted at the time of follow-up indicated a possible risky/harmful pattern of alcohol consumption or alcohol dependence syndrome among the patients (>8 points). The comparison group consisted of 20 psoriatic patients and AUDIT <8 points. The BSA and PASI scales were used to determine the severity of psoriasis, and the DLQI questionnaire assessed patients' quality of life and how they felt during the week preceding the survey. RESULTS As the amount and frequency of alcohol consumed increased, the exacerbation of lesions measured according to the PASI and BSA scales was significantly higher (P<0.05), and the quality of life decreased (P<0.05). We noted that inadequate and excessive dietary intake of total protein, total fat, and assimilable carbohydrates were associated with statistically significantly higher values of BSA and PASI scores and, thus, more severe psoriatic lesions (P<0.05). CONCLUSIONS An unbalanced diet, alcohol abuse, and smoking negatively affect the course of psoriasis vulgaris, hence the importance of patient education.