From the appearance, the head of non-poisonous snakes is oval, the tail is slender, and the pattern on the body surface is not obvious, such as red snake and black snake. The head of a poisonous snake is triangular, with a big neck and a thin tail. The tail is short and suddenly tapered, and the skin pattern is bright, such as Agkistrodon halys, Agkistrodon halys with white eyebrows, bamboo leaves, cobra, golden ring snake, and silver ring snake (except the head of cobra and silver ring snake). From the wound, because all poisonous snakes have fangs, there will be two big tooth marks on the wound, but the wounds left by non-poisonous snakes are in a neat row. From the time point of view, if there is redness and pain within 15 minutes after the bite, it may be bitten by a poisonous snake. ② First aid after being bitten by poisonous snakes. Don't run violently after a bite to slow down the absorption and diffusion of snake venom in the human body and reduce the systemic reaction; Remember the shape of the wound and inform the emergency medical staff in detail. If the snake is bitten to death, take the dead snake away so that the medical staff can deal with it correctly in time. After being bitten by a poisonous snake, you should immediately tie a soft rope or belt above the wound to block venous blood and lymphatic reflux, reduce the absorption of venom and prevent the spread of toxin; Emergency detoxification. Immediately wash the wound with Leng Cha, cold boiled water or spring water. If possible, use physiological saline, soapy water, hydrogen peroxide, 1/1000 potassium permanganate solution and 1/1000 nitrofurazone solution. Detoxification by stabbing. Use a clean small Miao Dao, scabbing knife, triangular needle or other clean and sharp tools to puncture the wound, not too deep. Based on the principle of cutting the skin between two fangs, or use a small Miao Dao to stab several holes in the skin around the wound, the blade is as big as a grain of rice, so as not to block the wound and make the venom flow out. After the knife is stabbed, the wound should be cleaned immediately and squeezed from top to bottom. If the venom in the wound can't flow out smoothly, you can use the method of sucking toxin, cupping and putting a rubber tube on the front end of the syringe to suck out the venom. You can suck directly through your mouth when you don't have tools, but you must pay attention to safety, spit while sucking, and rinse your mouth with clear water every time. What kind of snake medicine is used for oral administration and external application should be used flexibly on the principle that it can be collected immediately in the local area at that time. ③ Avoid being bitten by snakes. When walking in Shan Ye, don't just stick your hand in a tree hole or a crack in a rock, where snakes rest during the day. Holding a small stick or branch in your hand is also an effective way to avoid being bitten by a snake.