The influence of histamine (1 and 8 μg/kg) and sodium hypochlorite (SH; 5 and 20 mg/l) on the course of free radical processes in the spleen of rats on the 1, 7, 14 th day of the experiment, and also after the rehabilitation period (21 day). It has been established that histamine in both concentrations reduced the content of hydroperoxides by about 50 %. At a lower dose, the accumulation of TBА-reactive products slowed down during the experiment, while for higher such an effect was detected on 1 day , and the opposite – on the 7th. During this time, the activity of superoxide dismutase and catalase significantly increased (by 108 and 19 % respectively). he simultaneous injection of histamine (1 μg/kg) and SH in animals at a lower concentration resulted in the recovery of TBA-reactive products to normal at the initial stage of the experiment and after 14 days, however, their 7th content decreased by 20 % relative to the control values. Comparing this figure with a group of animals that were given histamine only (a 40 % decrease in accumulation relative to normal), it was higher. SH and its combined action (20 mg/l) with biogenic amine did not cause tread influence on free radical processes. Thus, at low doses of histamine and SH, the latter adjusts the parameters of the prooxidant-antioxidant state of the spleen, which is a positive effect.