The consition was studied of the pro- and antioxidant system in psoriatic patients. The groups of the examinees comprised 44 patients in the progressive stage of dermatosis and 16 patients in its stationary stage. Examined in the study was also a group of control subjects (16 and 10 patients respectively) and 15 healthy volunteers. The group of those patients presenting with a progressive process demonstrated increased indices for both lipid peroxidation and antioxidant defence. Examination of patients in the stationary stage of psoriasis revealed a significant intensification of processes of lipid peroxidation (rise in malonic dialdehyde, in dienic conjugates, and enhanced chemiluminiscence) associated with a decline in the activity of processes of the antioxidant defence. Expediency is proved of differentiated employment of antioxidant preparations depending on the stage of psoriasis.