Background. The increase in infectious and non-infectious diseases occurrence during pregnancy prompts scientists to search for substances that can fight these ailments. This especially applies to natural substances that have virtually no side effects. These include substances obtained from medicinal leeches. These substances have a wide range of therapeutic effects; as to their practical use, all preclinical studies must be completed. This particularly refers to the presence of an embryotoxic effect. The aim of this work was to investigate the effect of the water-salt extract of the medicinal leech Hirudo verbana Carena, 1820 on the general course of embryogenesis in rats when administered intraperitoneally. Materials and Methods. The work was performed on female non-linear white rats. Two experimental groups of animals were injected intraperitoneally with a water-salt extract of the medicinal leech at a concentration of 5 μg/g of the animal, in a volume of 0.5 mL, three times before mating and three times during pregnancy every 3 days. Two control groups were injected intraperitoneally with physiological saline according to the same scheme as the experimental groups. Subsequently, one of the control and experimental groups underwent euthanasia, dissection of the abdominal cavity and uterine horns on the 20th day of pregnancy. We analyzed the total number of corpora lutea of pregnancy, the number of live and dead fetuses. Fetuses were weighed, examined for the presence of skin hematomas, mutilations, and external abnormalities in the development of internal organs. The other two groups of control and experimental animals were left until the offspring were born. Then the females of both groups were weighed, and their general condition was assessed. Newborn rats were examined, weight and body length were determined, mortality was recorded from the beginning of birth to 15 days, the presence of skin hematomas, mutilations, and external anomalies of the development of internal organs were checked. Results and discussion. The study established that the intraperitoneal injection of a water-salt extract of a medicinal leech before and during pregnancy in female rats does not cause any toxic effect during embryogenesis and at the early stages of post-embryonic ontogenesis. During the external examination of fetuses and offspring in both groups, no developmental anomalies were noted, all organs in both groups were of normal topography and size. The number of subcutaneous hematomas in the experimental group of fetuses compared to the control group decreased by an average of 50%, postnatal mortality decreased by an average of more than 3 times, as well as an increase in body weight in females, an increase in body weight and body length in the fetus and offspring in the early post-embryonic period ontogenesis (p <0.05). Conclusion. Intraperitoneal administration of a therapeutic dose of a water-salt extract of the medicinal leech to female rats before and during pregnancy, after every three days, does not have any toxic effect on the course of embryogenesis and later in early post-embryonic ontogenesis.