In movies, people often suck the venom out of a snakebite. But this does not work. In one test, doctors put fake venom into the legs of eight men.

Then they used a suction tool for 15 minutes. It took out only 0.04 percent of the fake venom. If a snake bites you, stay calm, keep still, and go to a hospital quickly.

Sucking venom out of a snakebite is a famous scene in movies, but it does not help. In 2004, American emergency doctors injected a mock venom into the legs of eight healthy men. Three minutes later, they used a commercial suction pump for 15 minutes. It removed only 0.04 percent of the mock venom.

Venom spreads quickly into the tissue around the bite, so it is very hard to pull back out. Sucking with your mouth can also cause infection and delay treatment. Britain's NHS also warns against cutting the wound or tying it tightly. The only specific treatment is antivenom given in a hospital, so getting there fast is what matters most.

In films, someone always sucks the venom out of a snakebite. Medical research says it does not work. In a 2004 study, emergency physicians used a curved needle to inject a radioactively labeled mock venom 1 cm deep into the legs of eight healthy male volunteers.

Three minutes later, they applied a commercially available suction device for 15 minutes. It removed just 0.04 percent of the injected material, and what it drew out was mostly blood-tinged fluid. A commentary published alongside the study stated bluntly that such devices do not remove venom.

Venom spreads quickly through the surrounding tissue and into the lymph and bloodstream. Sucking by mouth adds more risks, such as infection from oral bacteria and delays in getting to care. The study had its limits. Only eight people took part, and mock venom may not behave exactly like the real thing.

Britain's NHS gives clear advice anyway. Do not suck, cut or tightly bind the wound, and avoid aspirin or ibuprofen. Snakebites kill more than 100,000 people a year, according to a 2017 review, and the only specific treatment is antivenom given in a hospital.