What are the medicinal values and effects of leeches?
The leech, commonly known as the bloodworm, was already recorded in the Shennong Bencao Jing (Classic of Materia Medica) and has high medicinal value. It grows and reproduces in inland freshwater waters and is a traditional special medicinal aquatic animal of China. Its dried product, after being steeped and prepared, is used in traditional Chinese medicine, with effects in treating stroke, high blood pressure, clearing blood stasis, amenorrhea, and traumatic injuries. Let us now take a look at what medicinal values the leech has!
The medicinal value of leeches
[Nature and flavor] Neutral in nature, salty and bitter in flavor.
[Meridian entry] Enters the liver meridian.
[Effects] Breaks blood and expels stasis.
[Indications] Used for amenorrhea, abdominal masses, and traumatic injuries.
1. Effects on blood
Hirudin can prevent thrombin from acting on fibrin and hinder blood coagulation. Hirudin is not destroyed by heat or ethanol. Leeches can also secrete a histamine-like substance, which can dilate capillaries and increase bleeding. The alcohol extract of leeches has a stronger inhibitory effect on blood coagulation than gadflies, insects, and peach kernels, and the alcohol preparation of leeches has a stronger effect than the water preparation. 20mg of hirudin can prevent the coagulation of 100g of human blood. The water extract of leeches has a significant inhibitory effect on ADP-induced rat platelet aggregation, and can also significantly inhibit platelet aggregation in normal humans, with an anti-thrombotic effect.
Experiments show that leeches have a strong fibrinolytic effect on fibrin in vitro, and their activity is significantly higher than that of Salvia miltiorrhiza and rhubarb; they also have fibrinolytic activity in vivo, and can significantly shorten the euglobulin lysis time (ELT) in rabbits. Therefore, leeches can activate the fibrinolytic system and dissolve thrombi. Some reports also point out that hirudin has a significant inhibitory effect on experimental thrombus formation and has a dissolving effect on experimental venous thrombosis caused by thrombin. The water extract of leeches can reduce the whole blood specific viscosity and plasma specific viscosity in rats, and shorten erythrocyte electrophoresis time. Clinical studies show that leeches can improve the thick, viscous, and aggregated state caused by abnormal hemorheology in patients with ischemic cerebrovascular disease.
2. Effects on the cardiovascular system
Some reports point out that leeches have a certain effect of increasing myocardial nutritional blood flow and have a protective effect on tissue ischemia and hypoxia. Hirudin can counteract coronary artery spasm in rabbits caused by pituitrin and has a therapeutic effect of inhibiting myocardial ischemia. Leeches can significantly reduce aortic atherosclerotic plaques, promote collagen fiber proliferation within the plaques, and reduce cholesterol crystals. This suggests that leeches have potential application value in the prevention and treatment of atherosclerosis.
Leeches can dilate capillaries, improve microcirculation, and increase renal blood flow. Their effect of improving microcirculation is similar to that of heparin, only the duration of action is short. Experiments show that leeches can dilate peripheral blood vessels, increase blood flow, and reduce vascular resistance, and this effect is similar to that of papaverine hydrochloride.
3. Effects on pregnancy
Experiments show that leeches have a terminating effect on pregnancy in mice at all stages (including implantation and the early, middle, and late stages of pregnancy). Different routes of administration all have a good terminating effect on early pregnancy. If exogenous progesterone is injected simultaneously with leeches, premature birth can be prevented. Leeches have an inhibitory effect on decidual lesions.
4. Other effects
Leeches have a significant lowering effect on cholesterol and triglycerides in rabbits with experimental hyperlipidemia.
Hirudin has an inhibitory effect on tumor cells and a certain inhibitory effect on the growth of mouse liver cancer. Because leeches have a high anticoagulant effect, they are beneficial for anticancer drugs and immunologically active cells to penetrate cancer tissue and kill cancer cells.
Suitable and contraindicated uses of leeches
Contraindicated for those with weak constitution and blood deficiency, those without stagnant blood stasis, and pregnant women.
① Rihua Yu Bencao: “Fears lime.”
② Bencao Yanyi: “Fears salt.”
③ Pinhui Jingyao: “Must not be taken during pregnancy.”
Selected medicinal formulas for leeches
1. To treat irregular menstruation in women, and also to treat men with bladder fullness and urgency with blood stasis: thirty leeches (prepared by heating), thirty gadflies (remove wings and legs, prepared by heating), twenty peach kernels (remove skin and tips), and three liang of rhubarb (soaked in wine). Grind the above four ingredients into powder, boil with five sheng of water and reduce to three sheng, remove the dregs, and take one sheng warm.
2. To treat blood stasis in the abdomen of women, irregular menstruation, either stopping or coming, and fullness and urgency in the heart and abdomen: three liang of peach kernels (soaked in hot water, remove skin, tips, and double kernels, stir-fried with bran until slightly yellow), forty gadflies (stir-fried until slightly yellow, remove wings and legs), forty leeches (stir-fried until slightly yellow), and three liang of Sichuan rhubarb (chopped and slightly stir-fried). Pound the above medicines and sieve into powder, mix with refined honey and pound over a hundred times, and make into pills the size of parasol tree seeds. For each dose, take fifteen pills on an empty stomach with hot wine.
3. To treat amenorrhea, or postpartum lochia, with pain in the umbilical and abdominal region: four liang of prepared rehmannia, fifty each of gadflies (remove heads, stir-fry the wings), leeches (stir-fried with glutinous rice until yellow, remove the glutinous rice), and peach kernels (remove skin and tips). Grind the above into powder, make honey pills the size of parasol tree seeds. For each dose, take five or seven pills on an empty stomach with warm wine.
4. To treat dripping hemorrhage with continuous bleeding: prepare leeches and sieve, take about one qian with wine, twice a day, and once the bad blood is dissolved, recovery occurs.
5. To treat fractures: leeches, dried on a new tile, made into fine powder, mixed with hot wine and taken one qian; after the time of a meal, the pain may ease, and with one more dose, the pain stops. Then apply fracture medicine and secure it with something to hold it in place.
6. To treat metal wounds, blows and injuries, falls from heights, being crushed by wood or stone, internal damage with blood stasis, heart and abdominal pain, inability to urinate or defecate, and near death from qi exhaustion: half a liang of red leeches (slowly stir-fried with lime until scorched yellow), two liang of rhubarb, and two liang of black pharbitis seed. Grind each of the above into fine powder. For each dose, take three qian mixed with hot wine. After the time it takes a person to walk four or five li, again take two qian of pharbitis seed powder mixed with hot wine to urge it on. The bowels must move to discharge the bad blood, either in clumps or in pieces, and when the bad blood is completely gone, recovery occurs.
7. To treat pain from injured bones and fractures: leeches (stir-fried with glutinous rice until yellow, remove the rice), white silk (burned to ash), myrrh (ground separately), and frankincense (ground separately) in equal parts, and fifteen tufts of blood residue (a young boy's hair) (burned to ash). Grind the above into powder. Those over fifty take one qian, those under twenty take half a qian, and children take half a character, taken with warm wine.
8. To treat erysipelas in children: use several leeches, place them on the red and swollen area, and let them suck out the toxic blood.
9. To treat early-stage red swelling of a back carbuncle: place (live) leeches on the swelling and let them drink blood. (After the leeches suck blood, their abdomens) swell and they fall off on their own; keep them alive by raising them in fresh water.