Treatment of the disease “COVID-19 – POST-COVID SYNDROME” requires the mandatory inclusion of detoxification methods in the technology of treatment and rehabilitation. The paper reflects the experience of using medical leeches in the context of the author’s “System Method of Leeching” in cases where intoxication was dominant in the “Clinical Image of the Disease”. The mechanism of action of medical leeches, which were successfully used in case of intoxication of patients with different pathologies, including “COVID-19 – POSTCOVID SYNDROME”, is considered.