Snakebites: First Aid and Prevention

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Warm weather wakes humans up from their hibernation, but it also wakes inhabitants of the Great Outdoors as well, such as snakes. Inevitably some hiker, camper, or hunter experiences a face-to-face (or face-to-ankle) encounter with a slithering serpent.

Of the 3000 species of snakes on planet Earth, only about 400 are venomous. In North America, those that inject venom into their victims are either pit vipers or elapids. Pit vipers include species of rattlesnakes, water moccasins (cottonmouths), and copperheads. One species or another exists everywhere in the U.S. except for Maine, Alaska, and Hawaii. Elapids include coral snakes, found mostly in the South.

A word about venom: Notice I don’t say “poison”. Poisons are absorbed in the gut or through the skin, but venom must be injected into tissues or blood via fangs or a stinger. Strangely, it’s usually not dangerous to drink snake venom unless you have a cut or sore in your mouth. Having said that, please don’t try this at home.


Pit vipers account for most snakebites in North America. The “pit” refers to a heat-sensing organ located between the eye and nostril on each side of a triangular head. The eyes have slit-like pupils. Pit vipers include:

Rattlesnakes: Of all pit vipers, rattlesnakes contribute the most to snake bite statistics in the U.S. They get their name from a structure at the end of their tails which makes a loud rattling noise when shaken. The “rattle” serves as a warning to discourage nearby threats.

Copperheads: The copperhead looks similar to a rattlesnake but without the rattle. As the name suggests, it is often copper-colored or pinkish-tan with darker bands.

Water Moccasins: These snakes are very comfortable in water. This snake has no rattle, so is relatively silent, as if walking in “moccasins”. Its response to threats is opening its mouth wide and exposing its whitish oral cavity before biting. This behavior gives it the nickname “cottonmouth”. The water moccasin may have a pattern when young, but as an adult is almost black in color. Its thick body differentiates it from other water snakes, which tend to be slender.


Coral Snakes are related to the king cobra. They’re brightly-colored but unassuming creatures that are rarely aggressive. Their small fangs are less effective in delivering venom than pit vipers. A coral snake tends to deliver venom by holding on and “chewing” on its victim, unlike vipers, which strike and let go quickly.

The marks left by venomous snake bites have a distinct appearance due to the hollow fangs at the front of the mouth. This differs from non-venomous snakes, where the bites have a more uniform appearance. 

Not every bite from a venomous snake transmits toxins to the victim; indeed, 25-30% of these bites will be “dry” and seem no worse than a bee sting.  This could be due to the short duration of time the snake had its fangs in its victim or whether the snake had bitten another animal shortly beforehand.


Non-venomous bites have been described as anywhere from mild to a bee sting to worse. Certain snakes like pythons may bite and hold on as a feeding behavior, having mistaken you for a nice juicy rodent. Pulling away may cause the skin to tear, but the snake usually releases when it realizes its error. Cleaning with soap and water plus, perhaps, an antibiotic ointment or oral antibiotic may be appropriate (as well as a tetanus shot). A small amount of bleeding may occur.

In a venomous bite, a painful burning sensation occurs almost immediately. Swelling at the site may begin as soon as five minutes afterwards, and may travel up the affected area towards the body core.  You might be surprised to learn that snake venom injected into soft tissue mostly travels throughout the body via the lymphatic system, not the blood. That’s why it may take a while to see the full effect.

It’s possible to be allergic to the snake venom as well as experience the effect of the toxin. An Epi-Pen or other epinephrine autoinjector would be useful here.

Pit viper bites are “hemotoxic”, meaning they tend to cause bruising and blisters at the site of the wound.  Numbness may be noted in the area bitten, or perhaps on the lips or face.  Some victims describe a metallic or other strange taste in their mouths. Serious bites might cause spontaneous bleeding from the nose or gums, irregular heart rhythms, or difficulty breathing.  The soft tissue in the area of the bite might deteriorate, a process called necrosis, something more common in water moccasin bites.

Coral snake bites, however, are “neurotoxic” and will cause mental and nerve issues such as twitching, confusion, and slurred speech.  Later, nerve damage may cause difficulty with swallowing and breathing, followed by total paralysis. Luckily, there are many fewer coral snake bites than pit viper bites in the U.S.

ASIDE: Coral snakes appear very similar to their look-alike, the non-venomous king snake.  They both have red, yellow, and black bands and are commonly confused with each other. The old saying goes: “red touches yellow, kill a fellow; red touches black, venom it lacks“.  In other words, if the red band is next to the yellow band, it’s a deadly coral snake. If the red band touches the black band, it’s a non-venomous king snake. It should be noted that this rhyme only applies to coral snakes in North America.

The good news is that only about five deaths occur annually in the U.S. out of several thousand bites.


An ounce of prevention, they say, is worth a pound of cure.  High-top boots and long pants are always a sound strategy when hiking in the wilderness. It’s important to be aware of where you’re putting your hands and feet.  Be especially careful around areas where snakes might like to hide, such as hollow logs, under rocks, or in old shelters. Wearing sturdy work gloves would be a wise precaution if you can’t avoid these places.

High tops are a must

If you let snakes know you’re near, they tend to leave the area. Snakes have no outer ear, so treading heavily creates ground vibrations more easily “heard” by them than, say, shouting. Some snakes like to be active at night, especially in hot weather. This means that outdoor activities are best with a good light source.


The standard treatment for a venomous snake bite is “anti-venin”, something capable of neutralizing a specific toxin. Urgent care centers might not have it, but most hospitals will. The quantity given is often the same for children and adults, as you are treating the venom, not the patient. In severe envenomation cases, several injections might be needed.

That’s great but in survival scenarios, this product will be a scarce commodity. If there’s no help coming:

•             Keep the victim calm. Stress increases blood flow, thereby endangering the patient by speeding the venom into the system.

•             Stop all movement of the injured extremity. Movement transports the venom into the circulation faster, so do your best to keep the limb still.

•             Clean the wound thoroughly to remove any venom that isn’t deep in the wound.

•             Remove rings, bracelets, and anklets from an affected extremity. Swelling is likely to occur and can be severe.

•             Keep the victim hydrated

•             In coral snake bites, you can wrap with bandages, looser than a pressure dressing but further up the limb.  This is usually not done with pit viper bites.

•             Similarly, avoid tourniquets, which do more harm than good by concentrating the venom in the area of the bite, causing more local damage.

•             Draw a circle around the affected area.  As time progresses, you will see the area shrink if it improves or grow if it worsens. By the way, this is a good strategy to follow for any local reaction, soft tissue infection, abscess, or hematoma.

The limb should then be rested and, if needed, immobilized with a splint or sling.  The less movement there is, the better. Keep the patient on bed rest, with the bite site at or lower than the level of the heart, for 24-48 hours. Too high and venom spreads more quickly. Below the level increases the risk of local damage, and at the level of the heart, well, either may happen. 12 hours without any major symptoms, you’re probably ok.

This strategy also works, by the way, for bites from venomous lizards, like Gila monsters.


It is no longer recommended to make an incision and try to suck out the venom with your mouth.  The amount of venom removed is thought to be very little and oral bacteria could introduce an infection. Snake bite kits are available for your backpack, but are out of favor with most wilderness medical professionals. We don’t use them. The Sawyer Extractor (a syringe with a suction cup) is modern and compact, but ineffective in eliminating more than a very small fraction of the venom.

There are a number of natural remedies that work well with insect venom, less hard data that they do anything for snakes. Plantain chewed and then applied to the bite wound is suggested by Dave Canterbury; if there’s no antivenin, it’s an option but beware of oral bacteria.

Interestingly, snake bites don’t cause infections as frequently as bites from cats, dogs, or humans.  As such, antibiotics are used less often, especially for smaller wounds. Water moccasin bites are an exception. Tetanus is still a concern.

It’s important to realize that a snake doesn’t always slither away after it bites you.  It’s likely that it still has more venom that it can inject, so move out of its territory or abolish the threat in any way you can. Killing the snake may not render it harmless, however: it can reflexively bite for a period of time.  

Elapids and pit vipers may respond differently to an encounter with a human. Coral snakes are not as aggressive as pit vipers and prefer fleeing to attacking.  Once they bite you, however, they tend to hold on. Rattlesnakes prefer to bite and let go quickly. Unlike elapids, though, pit vipers may be reluctant to relinquish their territory to you, so leave the area as soon as possible.

Snakes can be dangerous, but they want to avoid you as much as you want to avoid them. Most snakebites are the fault of an unwary victim or someone actively trying to handle or otherwise disturb the animal. Keep an eye out, wear decent gear, and both you and the snake can coexist in the Great Outdoors.

Joe Alton MD

Joe Alton MD

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