A medicament based on antibodies contains an activated form of ultra-low doses of monoclonal, polyclonal, or natural antibodies to endothelial nitric oxide synthase (NO synthase), the activated form being prepared by multiple consecutive dilutions and exposure to external factors, preferably according to the homeopathic technology. A method of treating erectile dysfunctions and vegetative disturbances of male climax by regulating the level of cyclic guanosine monophosphate (cGMP) in the cavernous bodies on sexual stimulation, the method being characterized by the use of activated forms of ultra-low doses of antibodies to the entire molecule of the endothelial NO synthase or to its polypeptide fragments, activated forms being prepared by multiple consecutive dilutions and exposure to external factors.