Most snakes aren't dangerous to people. Only about 15% of snakes worldwide and 20% in the United States can inject poison when they bite. These snakes are called venomous. In North America, these include the rattlesnake, coral snake, water moccasin, also called cottonmouth, and copperhead. Their bites can cause serious injuries and sometimes death.

Most venomous snakes in North America have eyes like slits and are called pit vipers. Their heads are triangle-shaped and they have fangs. One exception is the coral snake, which has a cigar-shaped head and round pupils. Nonvenomous snakes typically have rounded heads, round pupils and no fangs.

Most snakes aren't dangerous to people. Only about 15% of snakes worldwide and 20% in the United States can inject poison when they bite. These snakes are called venomous. In North America, these include the rattlesnake, coral snake, water moccasin, also called cottonmouth, and copperhead. Their bites can cause serious injuries and sometimes death.

If a venomous snake bites you, call 911 or your local emergency number right away, especially if the bitten area changes color, swells or is painful. Many emergency rooms have antivenom drugs, which may help you.

If possible, take these steps while waiting for medical help:

• Move far away from the snake.
• Stay still and calm.
• Remove any jewelry, watches or tight clothing before swelling starts.
• Sit or lie down so that the bite is in a neutral, comfortable position.
• Clean the bite with soap and water. Cover or wrap it loosely with a clean, dry bandage.

• Don't use a tourniquet or apply ice.
• Don't cut the bite or try to remove the venom.
• Don't drink caffeine or alcohol.
• Don't take pain-relieving medicine, such as aspirin, ibuprofen (Advil, Motrin IB, others) or naproxen sodium (Aleve). Doing so can increase your risk of bleeding.
• Don't try to catch or trap the snake. Try to remember its color and shape so that you can describe it. If possible, take a picture of the snake from a safe distance. Knowing what kind of snake bit you can help with treatment.

Most snakebites happen on the arms, wrists or hands. Typical symptoms of a nonvenomous snakebite are pain, injury and scratches at the site of the bite.

After a venomous snakebite, there usually is serious pain and tenderness at the site. This can worsen to swelling and bruising at the site that may move all the way up the arm or leg. Other symptoms are nausea, labored breathing and feelings of weakness, as well as an odd taste in the mouth.

Some snakes, such as coral snakes, have toxins that affect the brain and nerves. This can cause symptoms such as upper eyelid drooping, tingling fingers or toes, difficulty swallowing, and muscle weakness.

Sometimes, a venomous snake can bite without injecting venom. This is called a dry bite.

After you call 911 or your local emergency number, if possible, take these steps while waiting for medical help:

• Move far away from the snake.
• Stay still and calm.
• Remove any jewelry, watches or tight clothing before swelling starts.
• Sit or lie down so that the bite is in a neutral, comfortable position.
• Clean the bite with soap and water. Cover or wrap it loosely with a clean, dry bandage.

Most venomous snakes in North America have eyes like slits and are called pit vipers. Their heads are triangle-shaped and they have fangs. One exception is the coral snake, which has a cigar-shaped head and round pupils. Nonvenomous snakes typically have rounded heads, round pupils and no fangs.

• Don't tie off the bite area, called using a tourniquet, or apply ice.
• Don't cut the bite or try to remove the venom.
• Don't drink caffeine or alcohol.
• Don't take pain-relieving medicine, such as aspirin, ibuprofen (Advil, Motrin IB, others) or naproxen sodium (Aleve). Doing so can increase your risk of bleeding.
• Don't try to catch or trap the snake. Try to remember its color and shape so that you can describe it. If possible, take a picture of the snake from a safe distance. Knowing what kind of snake bit you can help with treatment.

If a venomous snake bites you, call 911 or your local emergency number right away, especially if the bitten area changes color, swells or is painful. Many emergency rooms have antivenom drugs, which may help you.