Introduction. Nitric oxide plays a key role in the development of inflammation. In this regard, it is promising to create a drug that reduces the production of nitric oxide in the focus of inflammation.Aim. To study experimentally the anti-inflammatory and analgesic effects of an inducible nitric oxide synthase inhibitor of an aminoguanidine derivative (LIS-M).Materials and Methods. The compound LIS-M in 1% aqueous solution of polyvinylpyrrolidone was administered intramuscularly at doses of 5, 10 and 20 mg/kg to 150 male Sprague Dawley rats and 50 male CD-1 mice with experimental models of inflammation and pain. The animals of the comparison group received diclofenac at a dose of 10 mg/kg, the animals of the control group received 1% aqueous solution of polyvinylpyrrolidone in an equivalent volume. The effect of the LIS-M compound on the course of experimental pathology and its analgesic potential ulcerogenic effect were evaluated.Results. In male Sprague Dawley rats, the LIS-M compound reduces acute exudative inflammation caused by injection of carrageenan, histamine or serotonin in plantar aponeurosis, inhibits the proliferation of granulation tissue and exudation around a cotton swab implanted under the skin, does not have an ulcerogenic effect. In male CD-1 mice, it weakens the pain reaction and increases the time before it occurs.Conclusion. The LIS-M compound at doses ranging from of 5 to 20 mg/kg has a pronounced antiexudative, antiproliferative and analgesic effect, not inferior to the action of diclofenac at a dose of 10 mg/kg, and does not have an ulcerogenic effect.