Comparative efficacy of ethanol and ethoxysclerol in sclerotherapy was studied among 37 patients with thyroid functional autonomy. It is shown that ethoxysclerol exceeds ethanol in efficiency of treatment, doesn't lead to depressed function of treated thyroid lobe and is better tolerated. Thereby ethoxysclerol should be always used as a sclerosant in patients with hormonal disturbances and multiple "hot" nodules.