The effect of Padma 28 on selected parameters of humoral and cellular immune reactions in rabbits subjected to experimental atherosclerosis was studied. The drug significantly reduced the size of atherosclerotic plaques in the aorta and restored to a varying extent the immune functions studied. The possible mechanism by which Padma 28 may exert its anti-atherosclerotic action is discussed in the scope of the immunological theory of atherosclerosis.