Aim. To investigate both toxic (hemolytic), and stimulating effects of two polymeric derivatives of guani- dine, in particular, polyhexamethylene guanidine (PHMG) and polyhexamethylene biguanidine (PHMB) both in the hydrochloride form, on eukaryotic cells depending on the concentration of the preparation; to study the possibility of using wound-healing and stimulating properties of these preparations in veterinary medicine. Methods. The hemolytic activity (toxicity) of PHMGH and PHMBH preparations in the concentration of 0.1% towards cattle and pig erythrocytes was determined by titration. Primary cell cultures of fetal kidney cells of calves and piglets were used to determine the influence of PHMGH and PHMBH both alone and in combination with the following biologically active substances: essential oils of Pinus sylvestris, Eucalyptus globulus, Citrus sinensis, Monarda didyma, ZnO nanoparticles (size c. 25 nm), and electrochemically acti- vated water – anolyte (Eh = –800 mV, pH 6.5–7.0). The concentration of the cells in the nutrient medium was determined via photocolorimetry. Results. It was found that depending on the concentration, PHMGH, and PHMBH preparations can cause the lysis of erythrocytes, and stimulate cell proliferative activity, including the formation of a monolayer of kidney cells of calves and piglets They cause hemolysis of cattle erythro- cytes in the concentrations commonly used for disinfection, i.e., about 0.1 %, in the average titers of 1 : 7 for PHMGH and 1 : 2.5 for PHMBH. Therefore, PHMBH shows greater hemolytic (biocidal) activity for cattle erythrocytes than PHMGH (in ≈2.8x). The high molecular weight fraction of PHMBH (M2 ≈ 2,000–7,000 Da) demonstrated a lower (in ≈2.4x) hemolytic activity than the low molecular weight basic fraction (M1 ≈ 500–2,000 Da). The experiments on the kidney cell cultures of pigs and cattle have shown that at non-toxic concentrations (10–5 %) PHMBH can effectively stimulate (from 27 to 65 % increase) the proliferative activ- ity of eukaryotic cells and accelerate the formation of a monolayer of cells. The combinations of PHMGH with some essential oils of medicinal plants also show a good effect (from 52 to 95 % increase), and PHMBH shows a good effect with oil of pine for pig kidney cells (20 % increase) and oil of horsemint for cattle kidney cells (67 % increase). Conclusions. PHMGH and PHMBH can possibly be used in agricultural production not only as disinfectants or antiseptics, but also in wound healing. Although their toxicity is also significant to eukaryotic cells, yet they can possibly be used in veterinary medicine in low concentrations (0.005–0.5 %) for the treatment of wounds of various origin, including burns, in the composition of ointments, gels, bandages, or plasters, which we have presently in investigation.