A method of treating a pathological syndrome includes the step of administering a pharmaceutical agent. The pharmaceutical agent contains an activated form of monoclonal, polyclonal or natural antibodies to an antigen. The activated form is prepared by repeated consecutive dilution and external treatment, predominantly based on homeopathic technology. The antigen is a substance or a drug acting as a direct cause of the pathological syndrome or involved in regulation of mechanisms of its formation. Thus, activated antibodies are raised against antigens of exogenous or endogenous origin, against autologous antigens, against fetal antigens and against anti-idiotypic antibodies.