AbstractThe pathobiological role of free radicals was demonstrated in hyperlipidaemia and in steatotic liver as well as in the immune response of lymphocytes and monocytes. Hyperlipidaemia has a suppressive effect on cellular immune responses, inhibits the mitogen induced lymphoblast transformation, diminishes the tumour necrosis factor alpha (TNF‐α) production of spleen macrophages and enhances spontaneous interleukin 1 (IL‐1) activity. A freeze dried extract ofSempervivum tectorumhas antioxidant, free radical scavenger and membrane stabilizing effects. The measured serum parameters were changed favourably afterSempervivum tectorumextract treatment. The beneficial effect ofSempervivum tectorumextract was also observed on the Con A stimulated blast transformation of splenocytes, on the lipopolysaccharide (LPS) triggered TNF‐α activity and on the spontaneous IL‐1 activity of spleen macrophages of hyperlipidaemic rats. The natural scavenger capacity was increased by treatment, initiating restoration of liver