If a small amount of leech enters the body without excessive tension and special treatment, because the acidic conditions in the gastrointestinal tract and esophagus are not capable of allowing the leech to exist in the body as a parallel parasite, and the acidic conditions in the stomach are strong enough to kill and completely destroy the leech, so simply a few leeches entering the body do not require special treatment. However, if a large number of leeches enter the digestive tract by mistake, treatment is needed at this time, and the methods usually taken are the conventional gastric lavage method, applying the method of vomiting and gouging to vomit them out, or applying the mechanical gastric lavage method to suck them out by intubation. It is also possible to perform high enema of mannitol by means of catheterization to completely empty the leech remaining in the intestinal tract.