Overview

Most snakes are not dangerous to humans. Only about 15% of snakes worldwide—and around 20% in the United States—are venomous, meaning they can inject poison when they bite. In North America, venomous snakes include:

  • Rattlesnake

  • Coral snake

  • Water moccasin (also called cottonmouth)

  • Copperhead

Bites from these snakes can cause serious injury or even death.

Venomous snakes in North America are typically pit vipers. They can be identified by:

  • Slit-like pupils

  • Triangular heads

  • Prominent fangs

The coral snake is an exception, with:

  • A cigar-shaped head

  • Round pupils

Nonvenomous snakes usually have:

  • Rounded heads

  • Round pupils

  • No fangs

When to Seek Emergency Help

Call 911 or your local emergency number immediately if:

  • You were bitten by a venomous snake

  • The bite area becomes discolored, swollen, or painful

Most emergency rooms have antivenom that can help treat the effects of the bite.

Symptoms

Snakebites most often occur on:

  • Arms

  • Wrists

  • Hands

Nonvenomous bites may cause:

  • Localized pain

  • Scratches

  • Minor injuries

Venomous bites typically cause:

  • Immediate and severe pain at the site

  • Swelling and bruising that can spread

  • Nausea

  • Difficulty breathing

  • Weakness

  • Strange or metallic taste in the mouth

Neurotoxic bites (such as from coral snakes) may cause:

  • Drooping eyelids

  • Tingling in fingers or toes

  • Trouble swallowing

  • Muscle weakness

Some venomous bites are dry bites, meaning no venom was injected.

Treatment

After calling 911, follow these steps if possible:

  • Move away from the snake to prevent another bite

  • Stay calm and still to slow the spread of venom

  • Remove jewelry, watches, or tight clothing before swelling begins

  • Sit or lie down with the affected limb in a neutral position

  • Clean the wound gently with soap and water

  • Loosely wrap the bite with a clean, dry bandage

What to Avoid

  • Do not apply a tourniquet or tie off the bite

  • Do not use ice

  • Do not cut the bite or try to suck out the venom

  • Avoid caffeine and alcohol

  • Do not take painkillers like aspirin, ibuprofen, or naproxen (they may increase bleeding)

  • Do not attempt to catch or touch the snake

If you can safely do so, try to:

  • Note the snake’s color and shape

  • Take a photo from a safe distance

This information can assist medical professionals with treatment.