In order to estimate toxicity of a novel composition, enterosorbent "ultrasorb", its toxic properties were studied in trials on experimental animals (white rats, mice, guinea pigs). Great variety of hematolytic, biochemical and pathohistologic parameters were determined to evaluate homeostasis. As a result of toxicity trials in acute and subacute experiments as well as in embryotoxic, teratogenic and allergic tests we have concluded that enterosorbent "Ultrasorb" is absolutely harmless and can be recommended for further trials in clinics.