Relevance. In recent years, there has been increased interest in medicinal plants, in particular, Potentilla alba L., used for the treatment of endocrine diseases, on the basis of which the thyroid drug - tablets for oral administration, containing 0,150 g of dry extract of roots and rhizomes of this plant. The dry extract of rhizomes and roots of Potentilla alba L. normalizes the functional activity of the thyroid gland, has an immunomodulatory and hypoli-pidemic effect in the rat model of experimental hypothyroidism. Aim. A study of the toxicity of tablets with dry extract of Potentilla alba L. with repeated administration to justify the conduct of clinical trials. Material and methods. The study of general toxic effects of tablets was carried out on 15 clinically healthy male rabbits of Soviet Chinchilla breed, which were given tablets in doses of 37,5 and 75 mg/kg for 90 days. Control animals received placebo tablets. Integral, hematological and biochemical parameters were recorded, electrocardiograms (ECG) were taken, and pathohistological studies were performed to detect health abnormalities. Results. Administration of tablets at 9- and 17-fold therapeutic doses had no effect on basic hematological, biochemical and ECG parameters charac-terizing functional state of liver, kidneys, cardiovascular system of experimental animals. Administration of tablets to rabbits in the tested doses caused a moderate dose-dependent decrease in their body weight gain, possibly related to the hypolipidemic effect. Pathohistological examination re-vealed changes that were dose-dependent: full-bloodedness of internal organs, including pituitary gland; stimulation of hematopoietic function charac-terized by increased spleen follicles and their confluence; inhibition of thyroid function and partially of spermatogenesis. At the maximum tested dose of 75 mg/kg, the studied drug had a selective specific pharmacological effect on the pituitary gland, causing a decrease in the size of basophilic cells. No irritating effect of the tablets on the mucosa of the gastrointestinal tract of animals was noted. Conclusion. The obtained results of the preclinical toxicological examination of tablets 0.150 g were included in the dossier on the drug prepared for transfer to the Ministry of Health of the Russian Federation for obtaining permission to conduct clinical trials.