From the WebMD Archives

May 25, 2018 -- Welcome to snake season. As the weather warms up, serpents will start to slither out of their winter hideouts and, inevitably, cross paths with humans. Such encounters may end in a trip to the emergency room.

“Throughout the spring and summer months, the numbers (of snakebite-related ER visits) double, triple, maybe even more than that,” says Diane Calello, MD, an associate professor of emergency medicine at Rutgers New Jersey Medical School in Newark. “It’s certainly a warm-weather phenomenon.”

The CDC estimates that as many as 8,000 people are bitten by venomous snakes in the U.S. each year. Such bites are rarely fatal. They kill about five people annually. But snake venom can cause serious harm.

“Venom causes pain and swelling and perhaps some blistering at the site of the bite, and it damages tissue,” says Bret Nicks, MD, a professor of emergency medicine at Wake Forest Baptist Health in Winston-Salem, NC. “Large amounts can cause internal bleeding.”

In the U.S., venomous snakes fall into one of two types: pit vipers and coral snakes.

Pit vipers share many physical traits, such as triangular heads, vertical pupils, and a pit between their nostrils and eyes. The snakes in this category include:

  • Rattlesnakes: There are many rattlesnake species throughout the U.S. “Among pit vipers, rattlesnake venom packs the most punch and causes the most problems,” says Calello, who's also executive and medical director of the New Jersey Poison Information and Education System.
  • Copperheads: These venomous snakes live mostly throughout the eastern U.S., but their habitat stretches as far west as Texas. “If you’re going to get bit by a venomous snake, this is the one you want because it doesn’t do a lot to you,” says Nicks.
  • Cottonmouths (aka water moccasins): Cottonmouth snakes can be found in the southeastern U.S. The like to be near water.

Coral snakes, says Nicks, live mostly in Florida and Georgia. They are black and red with white or yellow bands.

Snake Venom

Pit vipers account for many more bites than coral snakes, but bites from either are not always poisonous. When they are, the amount of venom can vary. This is because snakes control the release of their venom: The greater the threat it perceives, the more dangerous its bite. Nicks says that one in four pit viper bites are “dry,” or free of venom, while 50% of coral snakes’ bites deliver venom.

You’ll know that you’ve been poisoned by a pit viper if pain and swelling appear around the bite. Snakes most often chomp down on the ankle or hand, says Calello, and symptoms will spread up the leg or to the shoulder, respectively.

Pit viper venom contains many different compounds, she says. Together, they destroy tissue and break down the proteins that allow your blood to clot. Both the tissue damage and the bleeding contribute to swelling.

“The swelling and destruction can occur within an hour,” says Calello, “but the damage is generally not permanent if it’s treated.”

Left untreated, the tissue damage will get worse. That can lead to the loss of a limb or fingers, says Nicks, a spokesman for the American College of Emergency Physicians.

“If you have enough venom to cause large amounts of tissue damage, it can become gangrenous when the tissue dies,” he says.

Bites from coral snakes have few immediate signs to show that you’ve been poisoned. It can take 12 to 18 hours before serious symptoms set in. The venom, which contains neurotoxins, affects the brain’s ability to control the body’s muscles. Your speech may become slurred, and it may be hard to swallow. You could also get weak muscles, blurred vision, and paralysis. The poison can eventually make it difficult to breathe. That can be fatal, but only one death from a coral snake has been reported since the 1960s. Bites from these snakes don't happen often. In Florida, where coral snakes are most common, poison centers respond to fewer than 50 cases each year.

Best Practices

What to do -- and not do -- if a snake bites you:

  • DO Get to an emergency room as soon as possible. Even if the bite isn't poisonous, you’re at risk of tetanus, a serious bacterial infection, if your shot isn't up to date.
  • DO Move the limb where the bite happened as little as possible. This will help slow the spread of the venom.
  • DO Take note of the snake’s appearance. Your description will help the doctor identify what bit you. (Your location will also be a clue.)
  • DO Note the time the bite happened so the doctor knows how much time has passed.
  • DO Remove any jewelry around the area of the bite before swelling begins.
  • DO Use Tylenol for pain, if needed.
  • DO Keep contact information for poison control nearby. Call 800-222-1222, or text POISON to 797979 to save the number in your phone.
  • DO NOT Try to capture or kill the snake. You risk a second bite.
  • DO NOT Try to suck out the venom. It doesn’t work, says Calello, and it puts you at risk of getting poison in your mouth.
  • DO NOT Use aspirin, ibuprofen, or other painkillers that thin your blood.
  • DO NOT Apply a tourniquet. Cutting off blood flow to the area of the bite may cause more tissue damage, says Calello.


Treatment for a snakebite depends on the type of snake and how severe your response to the venom is. Mild cases may require only cleaning of the bite and observation to be certain you’re not likely to have further harm. You probably will also have blood drawn in order to test for any clotting problems caused by the venom.

In addition to first aid, observation, and blood tests, treatment of more severe bites requires anti-venom, which counteracts snake venom’s effects so that your blood can clot normally.

“The anti-venom that exists really does an amazing job at reducing your pain and swelling in the short term and improving your long-term outcomes,” says Nicks.

Coral snake anti-venom is also quite effective, but it is no longer being produced, and supplies are dwindling. And according to the FDA, current stocks of coral snake anti-venom will expire on Jan. 31, 2019.

Most people bitten by a coral snake can be treated successfully without anti-venom, but treatment could mean a longer hospital stay and assisted breathing. Nicks says that the emergency department should coordinate with the local poison control center to find out if anti-venom is available. Fortunately, coral snake bites are rare.

Anti-venom can cause an immediate allergic reaction, so you will be monitored as you get it. Some patients have a delayed reaction, called serum sickness, up to 3 weeks after getting the anti-venom. Symptoms include fever, hives, itching, and joint pain.

Expect about 6 to 24 hours of observation in the hospital, says Nicks. And be prepared for discomfort after you leave.

“Symptoms can last 1 to 2 weeks, on average, after treatment,” says Calello.


Of course, it’s best to avoid snakebites altogether, and you can do that by not provoking them.

“Snakes found in the U.S. are not aggressive and only bite when they feel threatened,” says Nicks. “They’re not seeking you out.”

Nicks and Calello recommend the following when in snake country:

  • Pay attention to where you walk. A snake likely won’t bite unless you step on it.
  • Avoid alcohol in order to remain alert. (And smart, adds Nicks: “Drinking may lead you to grab a snake and swing it around.”)
  • Carry a walking stick to tap the ground in front of you. If a snake feels threatened, it will be more likely to attack the stick.
  • Wear boots and long pants to protect your ankles.
  • Wear a headlamp or carry a flashlight at night so you can see snakes before you have a surprise encounter.

Show Sources

Diane Calello, MD, executive and medical director, New Jersey Poison Information and Education System; associate professor of emergency medicine, Rutgers New Jersey Medical School, Newark.

Bret Nicks, MD, professor of emergency medicine and wilderness medicine specialist, Wake Forest Baptist Health, Lexington, NC.

CDC: “Venomous Snakes.”

FDA: “Expiration Date Extension for North American Coral Snake Antivenin (Micrurus fulvius) (Equine Origin) Lot L67530 through January 31, 2019.”

Florida Poison Information Center: “Antivenom FAQ.”

Juckett, G. American Family Physician, April 1, 2002.

Medscape: “Coral Snake Envenomation Treatment & Management.”

Scripps Health: “Serum Sickness.”

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