Mayo Clinic Health Library

Snakebites

Updated: 04-18-2012

Most North American snakes aren't poisonous. Some exceptions include the rattlesnake, coral snake, water moccasin and copperhead. Their bites can be life-threatening.

Of the poisonous snakes found in North America, all but the coral snake have slit-like eyes and are known as pit vipers. Their heads are triangular, with a depression (pit) midway between the eye and nostril on either side of the head.

Other characteristics are unique to certain poisonous snakes:

  • Rattlesnakes rattle by shaking the rings at the end of their tails.
  • Water moccasins' mouths have a white, cottony lining.
  • Coral snakes have red, yellow and black rings along the length of their bodies.

To reduce your risk of snakebite, avoid touching any snake. Instead, back away slowly. Most snakes avoid people if possible and bite only when threatened or surprised.

If a snake bites you

  • Remain calm.
  • Immobilize the bitten arm or leg, and stay as quiet as possible to keep the poison from spreading through your body.
  • Remove jewelry before you start to swell.
  • Position yourself, if possible, so that the bite is at or below the level of your heart.
  • Cleanse the wound, but don't flush it with water, and cover it with a clean, dry dressing.
  • Apply a splint to reduce movement of the affected area, but keep it loose enough so as not to restrict blood flow.
  • Don't use a tourniquet or apply ice.
  • Don't cut the wound or attempt to remove the venom.
  • Don't drink caffeine or alcohol.
  • Don't try to capture the snake, but try to remember its color and shape so you can describe it, which will help in your treatment.

Call 911 or seek immediate medical attention, especially if the area changes color, begins to swell or is painful.