What are the symptoms of a leech bite and how should it be treated?

When hiking in streams in summer, you often encounter leeches, also known as bloodsuckers (different from slugs). They are a valuable traditional Chinese medicinal material. Their saliva contains an anticoagulant substance called hirudin. In addition, it also contains heparin, antithrombin, and others, which can be used to treat conditions such as stroke, amenorrhea, angina pectoris, unexplained swelling and pain, tumors, cervical lymph nodes, arthritis, and more. Hirudin can help keep veins open after transplant surgery... and so on (that’s beside the point). So how do you deal with them?

Leeches mostly live in rice paddies, ponds, ditches, rivers, and similar places. They often attach to human skin to suck blood while secreting hirudin, which prevents blood clotting, numbs the wound, dilates blood vessels, and causes continuous bleeding (generally, the amount of blood a leech sucks will be lost again, but because this blood contains hirudin, which is harmful to the body, it must be completely removed—the wound will clot on its own).

Prevention:

The method to prevent leech bites is simple: avoid bathing or swimming in waters where leeches are abundant. If you must go due to research, labor, or other necessities, before entering the water, wear thick, long socks, tuck your pants into the socks, and tie the sock openings tightly—leeches won’t be able to get in. Wearing gaiters can also effectively prevent attacks from mountain leeches. Spraying insecticide, such as mosquito repellent or essential balm, or even mint oil, on your pants, shoes, and socks can repel mountain leeches. Sprinkling concentrated saltwater on these areas also works as a deterrent. When walking in damp areas, frequently reapply these to maintain effectiveness, as the potency may weaken or salt content reduce over time.

Choose camping sites in relatively dry areas with little grass—avoid camping by lakes, rivers, or streams. Frequently check your body for leech bites during rest breaks and remove any leeches promptly. When crossing rivers or streams with leeches, tuck your pants tightly into your boots, and check for attached leeches after coming ashore. Preferably drink boiled water and avoid water that may contain parasitic leeches. Tiny juvenile leeches are hard to spot—if ingested, they may parasitize the respiratory tract, esophagus, urethra, and other areas.

Treatment:

If you discover a leech has attached to you, follow these steps to handle it:

1) Never forcibly pull off the leech, because the harder you pull, the tighter its suction cups grip. If the leech is torn apart, its suction cups may remain in the wound, leading to infection or ulceration.

2) You can gently tap the area above the leech bite or lightly flick around the leech with your fingers to encourage it to release its grip and fall off. You can also apply substances like mentholated oil, tobacco water (water soaked with cigarette butts), table salt (an extremely important item in outdoor activities—you should always carry a small packet wherever you go), concentrated vinegar, alcohol (or liquor), chili powder, or lime onto the leech to make it relax its suction cups and detach on its own.

3) When bitten, calmly take out the salt you carry with you, sprinkle it on the leech, and soon you’ll notice it slowly wriggling—then you can gently remove it. If you want revenge, adding a stomp works too.

4) You can also burn it slightly—the leech will fall off. But be extremely careful with this method; otherwise, you might scald yourself before the leech lets go.

5) After the leech falls off, if the wound continues to bleed (which is usually the case), press it firmly with a clean finger or gauze. Bleeding typically stops after 1–2 minutes. Then apply gentian violet solution (also called crystal violet) or iodine tincture to the bleeding spot (iodine is another valuable item in outdoor gear—very versatile, we’ll introduce it in detail later). You can also dress the wound with gauze. Be sure to keep the wound dry to avoid infection. If bleeding continues, sprinkle some Yunnan Baiyao or hemostatic powder on the wound.

6) If the wound doesn’t bleed after the leech falls off, use force to squeeze out any dirty blood inside the wound (if you can’t bring yourself to do it, ask someone else—preferably not a significant other, to avoid misunderstandings). Rinse the area with baking soda water or clean water, then apply iodine, alcohol, or red mercury for disinfection.

7) If a leech enters the nasal cavity (you’ve hit the jackpot), try dripping honey into the nose to make it fall out. If it doesn’t work, fill a basin with water, have the person hold their breath, and submerge their nostrils in the water while gently agitating the water—the leech may be flushed out. (No one’s tried this yet.)

8) If a leech enters the anus, vagina, urethra, or similar areas (for guys, those vascular-rich regions are often leech hotspots—sprinkle salt or apply tobacco heat, but don’t ask a girl to help to avoid awkwardness—it gets pretty heated). Carefully inspect the affected area, then drip vinegar, honey, or anesthetic (such as 1% procaine or 2% lidocaine) onto the leech. Once it retracts, use tweezers to remove it.

In short, there’s no need to panic when encountering a leech. Just use the right method. Once again, don’t scream and frantically try to flick or pull it off the moment you see one. Even if you manage to knock or pull it off, that’s just the body—the head may still remain embedded in the skin, which can lead to infection.

Trailblazer Expeditions—professional outdoor adventure and self-driving tours.