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How to Survive Snake Bites – The Science of Antivenom

Avatar for Jodie Weston Jodie Weston  |  Updated: September 9, 2020
How to Survive Snake Bites – The Science of Antivenom

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In the event of a venomous snake bite, antivenom, sometimes called antivenin, is the only treatment. While these miraculous drugs cannot reverse the damage that the venom has already caused you, they do stop the venom in its tracks. So, how exactly does it work?

Of course, you’ll also want to know which snakes are venomous, how to avoid them, and what to do if you’ve been bitten by one. Snake safety has changed a lot over the decades, and there is lots of false information floating around, so you may need this refresher.

Poison or Venom?

Snakes are not poisonous, they are venomous. Venom is a group of proteins and enzymes which have a negative effect on the snake’s prey, from killing them, to immobilizing them, even to helping digest them. There are three main types of venom a snake can have (and they all can deliver more than one of these in a single bite):

  1. Hemotoxic: Hemo means blood, so this venom effects the blood. It can cause bleeding, make that bleeding (or the bleeding from the bite) worse by inhibiting your ability to clot (or scab). Then again, hemotoxins can also clot your blood so much that it can no longer flow, sometimes causing stroke or heart failure.
  2. Cytotoxic: Cyto means cell. This type of venom can break down cells, in a form of digestion. It can destroy your flesh, perhaps to the point that you lose your limb or life. Snakes commonly use this venom to begin digesting their prey.
  3. Neurotoxic: Neuro means nerves, so this venom effects the nervous system and the brain. These toxins will mess with your body’s most vital functions, from moving to breathing. Usually, these toxins are the fastest to take effect and can end in death by paralysis of your diaphragm.

These categories are an oversimplification. Each species of snake has developed a different chemical mixture to take down their most common prey. Indeed, even individuals within a species can have different venom. None were designed to target humans, but they can still kill us.

How Antivenom was First Made

Antivenom, sometimes called antivenin, was first produced by Albert Calmette in the 1890s. Calmette was a student of Louis Pasteur, who developed the “second wave” of vaccines. Calmette used the same kind of technique to create antivenom after witnessing a disaster in a Vietnamese village. Flooding had brought in a group of cobras, who bit forty people, killing four.

Calmette’s basic process was to inject horses with a small amount of snake venom, and wait for them to develop anti-bodies to the venom. Anti-bodies are a typical immune system response to venom and all sorts of illnesses, and the basis of vaccines. Humans just don’t make venom antibodies fast enough to save their life.

Horses are better adapted to survive snake bites. Plus, because horses are so large, it would take a large amount of the venom to kill them, making the process relatively safe. After, Calmette would collect some of the horse’s blood, and separate out the anti-bodies. Those anti-bodies could then be injected into a human, where they would fight off the venom.

How Exactly Do These Antibodies “Fight Off” the Venom?

The proteins in venom evolved to hook themselves onto cells and block them from interacting with other cells properly. For example, neurotoxins are the right shape to hook onto nerves. This is called binding, and it prevents the nerve from doing its job, of firing messages to other nerves.

When enough nerves are so disabled, whole sections of your brain or spinal cord can’t pass on their signal. It’s like cutting that part of your body off from the rest of it. The same goes for venom that targets blood or other cells, it disables them by hooking onto them.

When antivenom is administered it binds onto the neurotoxin itself, changing its shape. The neurotoxin is then like a puzzle piece that doesn’t fit into it’s spot. It can’t hook onto your nerves anymore, so the remaining nerves can still do their job. Eventually, your kidneys will send the now harmless toxins out of your body.

However, once the venom has hooked itself onto the cell, most antivenom cannot pry the venom loose. Usually, damage from venom is irreversible.

Modern Antivenom

Modern antivenom is essentially the same as the kind Calmette created, just an immune response from some other animal, given to humans in large doses. We can now separate out the working part of the anti-body from other proteins the animal produces, reducing the likelihood a severe reaction to the antivenom.

Once, people would become allergic to horses from using antivenom. Now, even those who are already allergic to horses can be given the antivenom, the doctors will simply treat the allergic reaction as well. However, because the process of creating the venom still requires a ton of time, equipment, and expertise (including keeping live snakes and other live animals) antivenom is quite expensive.

The only FDA approved antivenom in current production is CroFab. All American pit vipers are treated with CroFab, while Coral Snake bites are treated with North American Coral Snake Antivenin (NASCA). NASCA is now out of production, as the manufacturer decided it was too expensive to make. There is a limited supply of it remaining, so it is only used in the case of life-threatening reaction that other medical intervention cannot deal with.

Only one person has died of coral snake bites in the last five years. And, work has begun on a new coral snake antivenom patent.

This also means that all you need to know about the venomous snake which bit you is whether or not its a coral snake (in the continental United States, anyway, assuming this is not a pet or zoo snake). Treatment for all others will be the same.

How to Avoid a Snake Bite

Wear rubber boots which cover your ankles, and long pants. Also wear thick leather gloves, especially when dealing with wood piles or debris, which snakes can hide in. While walking, kick up in front of you to warn the snake, or use a walking stick to check the path in front of you. If you see a snake, leave it alone. Even if the snake is dead, its nerves still fire for hours afterward, and it will occasionally strike out and bite.

You should also be aware of what venomous snakes are in your area, so you know their typical habits, behaviors, and how to identify them. Here’s a guide to get you started.

Varieties of American Venomous Snakes

There are four main types of venomous snakes in the continental United States. There are many different species among each of these groups.



there are more than a dozen venomous rattlesnakes in the US, including both Diamondbacks, both Massagaugas, and more. They all have a rattle at the end of their tail, which they use as a warning. If you hear it, but can’t see the snake, freeze completely and look carefully. If you do not approach them they are very unlikely to bite you.


There are five species of copperhead snakes, most with the famous hourglass pattern on their back. When threatened these snakes will freeze instead of moving away like other snakes. Generally they will only bite if you touch them, or get rather close to touching them, but you should still give them a wide berth. Unobservant hikers who move towards a frozen copperhead are likely to step on them and receive a bite, so keep your eye out.

cottonmouth table rock mountain south carolina


There are only three cottonmouths in the US, the eastern, western, and Florida. They are also commonly called moccasins, of some variety. These are the most aggressive of the four snakes, and also can be found in water. They stand their ground and open their mouths at intruders, threatening that if you come closer they will bite.

Coral Snakes:

This is the only kind of snake in the US that is not a pit viper. You can distinguish a Coral from its lookalike snakes by using this rhyme: “red on black, friend of Jack; red on yellow, kill a fellow.” All other kinds of snakes, that are endemic to the continental US, are treated by the same antivenom, so all you need to know about your snake is whether or not it was a coral. Unless, that is, the snake was found in a zoo or private collection. After a snake bite the least important thing is to capture or kill the snake that bit you– do not waste your time.

Potential Venomous Snake Bite Symptoms

If one of these snakes bites you any of the following symptoms may follow, as quickly as seconds later:

– dizziness

– fainting

– shock

– pain, intense or moderate

– rapid heartbeat

– low blood pressure

– skin discoloration

– blurred vision

– swelling

– sweating

– numbness

– nausea

– vomiting

– tingling

– diarrhea

– thirst

– difficulty breathing

On the other hand, venomous snakes can bite without delivering any of their venom– but even if you’re not experiencing symptoms you should seek medical help right away. If you did get venom, we can’t say for certain which symptoms will effect you, because snakes can give out different amounts of venom, and even different types of venom.

How to Survive Snake Bites

All of this information, unless otherwise noted, has been gathered from Outdoor Alabama, which is run by the Alabama Department of Conservation and Natural Resources, as well as from New York Search and Rescue.

There is a lot of false information out there about how to deal with snake bites, mostly because studies have revealed new best practices over time. This information is very likely to change again, so be careful where you get your snake safety information from and insist those giving you advice be transparent about where they have gotten their information from.

Your general goal to survive a snake bite is two fold. First: get medical help immediately. Second: after help is on route, or while someone is calling an ambulance, prevent the venom from taking effect.

It’s important to differentiate between preventing the venom from taking effect and “stopping the spread” of venom. You actually don’t want to completely stop the spread of venom, because when it’s kept to a single area it’s more potent and will effect that area faster, possibly disfiguring or harming the limb beyond repair. So, you should never apply a tourniquet to a snake bite.

Instead, you should apply a light compression bandage roughly four inches above the wound (that is, closer to the heart), as if you’re wrapping a sprained ankle. This prevents the venom from spreading quickly within the specific muscles that were bit, while leaving the venom free to dilute itself and, ultimately, give you more time to get antivenom.

It’s also important to note that New York Search and Rescue advises to wrap the snake bite directly with gauze. The publication admits that this practice is controversial in America, while widely practiced in Australia. This is not a tourniquet, it is a wide gauze bandage wrapped tightly and taped down.

The other way to prevent the venom from taking effect is to stay calm, trying to keep your heart rate low. If you need to walk to get medical attention then you should, but if you have a working cellphone you should call 911, or be driven to a hospital.

Don’t try to drive yourself, you may faint at the wheel. While being transported to the hospital, you should use a loose splint to keep the limb as still as possible, in a position at heart level (preferably not above or below).

If you were wearing jewelry near the bite, take it off before you put on the splint. You’re going to swell up, and the jewelry is going to be very uncomfortable. Although, if there’s any chance you may have to walk, then do not take off your shoe. In all likelihood, you won’t be able to put it back on again.

The second part of surviving a snake bite is to seek medical attention. Calling an ambulance is not something we self-sufficient preppers like to do. But, even if you have antivenom on-hand you should go to the hospital (after someone administers the first dose, of course).

Some people have allergic reactions to antivenom. Or you could need many more doses of antivenom than you have on hand, twenty or more. Occasionally, there are further complications from the venom, like one poor man who had a heart attack just after suffering the snake bite. There are plenty of complicating factors from the bite itself, so when medical help is available, get it.

When medical help is not available, things get rough. You should follow all of the methods of preventing the venom from taking effect as outlined above. Hopefully, you’ve stocked up on antivenom before SHTF, and you have someone around to give it to you, and keep giving it to you. There is always the possibility that the snake did not give you venom, or did not give you enough to kill you, and that’s essentially all you can hope for in this situation.

Here’s a Quick Bullet list of the Do’s and Don’ts:


– seek medical attention immediately

– gently wrap above the wound with a wide cloth or gauze pad

– keep the limb still, unless you have to walk

– keep the limb at heart level, in a splint

Do Not

– wait to see how you feel before you seek medical attention

– take a risk or waste time trying to capture or kill the snake

– apply ice or heat to the bite

– cut the wound

– suck on the wound with your mouth

– use a suction device on the wound

– shock the wound with electricity

– drink alcohol, drink caffeine, eat, or take medications

Final Word – What Can you Really Do?

Your best strategy for snake preparedness is simply to know where to look for snakes, take appropriate precautions, and never approach them. If you look over this very interesting list of snake deaths in United States, you’ll see that most of the people dying from snakes in the modern era are those who handle them, or those who were bitten while hiking and were effected by the venom too quickly to get effective help.

For preppers, having a stock of CroFab on hand for when medical help may not be available is an essential. It is not currently FDA approved, which means there is no readily available means of procurement.

Most local clinics and hospitals do – however – keep it in stock.

In many ways, this is the ultimate “worst case” SHTF scenario if you live in an area where snakes are prevalent and local government has collapsed.

Unfortunately, most over the counter “snake bite kits” are not to be trusted as legitimate solutions. Most employ the “suction method” which is generally inadequate at removing the bulk of the venom (and may actually complicate the issue by aggravating the wound site). In a SHTF scenario, you may not have the luxury of “options”.

In this specific case (where medical treatment is NOT a realistic option and/or CroFab is unavailable), something like the the Sawyer Extractor Pump may be your only option.

Prevention may be your best chance of survival.

  • Invest in a good pair of high boots (cowboy boots or similar).
  • Acquire some snake repellent.

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12 Responses to “How to Survive Snake Bites – The Science of Antivenom”

  1. Pour turpentine or kerosine over a SNAKE BITE to draw out the poison. A lot of hunters have reported their hunting dogs bitten by rattlesnakes and even to the head and survived by the use of turpentine or kerosine use to clean the wound and draw out the venom. Turpentine is also used for quick and effective relief from painful wasp and bee stings. Country folk lore.

  2. I have been bitten by a rattler . Heavy boots and thick socks prevented a full dose of venom. I had a kit called extractor . I used it right away. Drove myself to the emergency room . Finally saw the doctor. He said at that point the antivenin would probably cause more harm than good . So he sent me home

  3. In 1976 my dad was bit by a coral snake in Dade County, FL.
    First we drove to Homestead Air Force Base then he was taken to the Homestead Hospital
    And finally taken to Coral Reef Hospital. They were better prepared to handle the heart attack he had in reaction to the antivenin. Bill Haast of the Miami Serpentarium was called in to give blood which saved my Dad.
    Besides saving my dad’s life, Mr. Haast gave us an autographed book he wrote and we gave him the coral snake. I highly recommend reading the story of Bill Haast.

  4. To say antivenom is the only treatment for snake bite is not correct. It is not even a good treatment, comparatively.

    Using a low-dose stun gun will stop the venom from working. The electric shock when properly applied will destroy the protein cells in the venom and neutralize it. It works the same for spider bites. I know.

    I have had 5 brown recluse bites. The first, I did not have a stun gun, and had huge physical problems. The last 4 times I had a gun and used it immediately after the bites. It completely neutralized the toxin, and within 30 minutes, one could not even find where the bite had been. It also works on wasp stings.

    I live in the deep country, and keep this handy tool handy at all times, because it works.

  5. Outdoor Life magazine had an article on snakebites in their October 1987 edition. It said that the doctors in South America had found that electricity applied to the area of the bite would neutralize the venom.
    I have a friend who is a professional trapper who is highly allergic to wasp and bee stings must less snake bites so I gave him a stun gun and told him to zap himself 8 times around the sting or bite if he was stung or bitten.
    Well he has been stung several times and been snake bit twice that I know of since then and the stun gun has worked every time.
    Instead od giving himself an shot and rushing to the hospital like he would do before he would just zap the area with several quick burst of the stun gun and it was if he had never been bitten.
    I also was bitten by a 4 1/2 foot cottonmouth at deer camp and used the plug wire of a 4 wheeler to shock the area around the bite. My friends wanted to rush me to the hospital but I refused and after about 30 minutes they admitted that the technique worked.
    My wife was bitten by a Brown Recluse spider on the back of her leg between the hip and knee and it was swollen with a nickel sized black bullseye. I zapped her 8 times around the bite and the next day the swelling and the bullseye was gone and the day after that the soreness left.
    Highly recommend carrying a small stun gun when you are in the woods or where you may be around venomous snakes, spiders, or bees.

  6. I was bitten by a Cottonmouth on the hand twice at age15 in 1967. The old Country doctor who treated me first immersed my hand in Hot water in which he had dissolved a large amount of Salt. I watched as probably Most of the Venom was drawn out of my hand into the Hot water. He then bandaged my hand with anti-bacterial salve in which he mixed a healthy amount of Salt. He then injected a small amount of Anti-Venom just under the skin. When I did not react I was given a full injection of Anti-Venom. When I removed the bandage the next day, it was soaked with Venom. One week later I suffered an Anaphylactic reaction to the Anti-Venom, and came close to dying. Whether I would survive another Dose of Anti-Venom is questionable. I would certainly try the Salt, and would advise that as part of Any treatment where possible. To say that Anti-Venom is the ONLY treatment is Short-sighted. People do react, and they don’t all Survive.

  7. Hi this is a very good article on snake bite ,and i just thought i would add a little about the wide bandage used in Australia we call it a pressure bandage and the way it is applied is thus ,if you are bitten on the arm or leg for example you would start wrapping at the bite site and then move down to your fingers or toes and from there wrap all the way up your arm or leg the reason it’s done this way is to restrict the flow of venom and it works very well when you arrive at a hospital they don’t remove the bandage until they know what has bitten you either by you saying or taking a swab from the bite site which means removing a bit of bandage i hope some find this helpful i was a snake rescuer for 12 years and had a few bites so i know this method very well cheers

  8. Wouldn’t it be useful to follow up “For preppers, having a stock of CroFab on hand for when medical help may not be available is an essential.” with some sources?

    • I don’t think I understand what you mean. Isn’t it just common sense that, if you’re prepping for when medical help won’t be around, you want the primary snake bite anti-venom on hand? Or do you mean you want a link to where you can buy it?

  9. Fascinating and informative article. I moved to Colorado from Minnesota 2 years ago and have been concerned about rattlers. This was very helpful in knowing how to avoid an encounter with one!

    Two questions: 1) Are antivenom kits available to the general public and if so, can you tell me where to buy them?

    2) Any information on how to keep dogs away from snakes? I am not so concerned for myself as I am for my little 12-lb dog, who would go after a snake in an instant and most certainly would not survive a bite.

    Thanks and love your site!

    • Many years ago I was able to get crotalid antivenin from the vet. It is expensive, must be kept refrigerated, and has a limited shelf life.
      Sadly a 12 pound dog vs rattlesnake would not have good odds of survival. There are some methods of discouraging dogs from bothering snakes, some would think the methods cruel, but it may keep a dog from getting bit, just do an internet search and see what you think.
      My most obnoxious dog managed to get bit by a copperhead, perhaps he has learned a lesson but that is doubtful. He was treated by a vet with antihistamines and antibiotics. Luckily, the bite was not efficient, and the copperhead is regarded as not as dangerous as a rattlesnake, however, always seek medical attention for you or your pet if bit by a snake. By the way keep some benadryl on hand to dose your dog until you get to the vet.

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