There are innumerable combinations of variables that affect the outcome of a snake envenomation. The size, age, and health of both the snake and the person bitten are important factors. The body temperature, even mood, of a particular snake in addition to the toxicity and quantity of venom delivered by that snake can all make a very big difference in the outcome of the bite.

Snakes have complete control over how much venom they inject anytime they bite. So one could get a “dry” bite, with no venom in it whatsoever.  Consequently, a particularly annoyed snake might inject its maximum amount.  Interestingly, studies have also shown that the toxicity of the venom in a particular snake can vary a small amount from season to season and even day to day.

The location of the bite is another consideration, along with route of injection, and even sensitivity and/or allergies of the person bitten. Add in the potential for a severe infection, and it is safe to say there are many variables that will affect the outcome of a snake bite.

Some snakes affect the nervous system with a neurotoxic venom; others have an effect on the tissue and blood with a hemotoxic venom. But, there are actually more than these two well-known types of toxins, as well as countless combinations of them. Examples are: myotoxins, cardiotoxins, haemotoxins, and neurotoxins. No snake possesses just one type because each snake tends to have a different combination of toxins. It is this variable combination that makes reactions to bites from different species so unique.

There are many misconceptions about what snake venom actually is. Snake venom is merely modified saliva, or a combination of many different proteins and enzymes.

The old way of categorizing venom indicated that some snakes have a neurotoxic venom (affecting the nervous system) and others have a haemotoxic venom (affecting tissue and blood). There are actually far more than two types of toxins, and countless combinations of these - myotoxins, cardiotoxins, haemotoxins, and neurotoxins, to name just a few.

No snake venom contains just one type of toxin – most snakes have a combination of toxins, and it's this variable combination that makes reactions to snake bites so different from species to species.

What is, and what do we mean by snake venom toxicity?  Toxicity is traditionally determined by how much venom it takes to kill a test animal. It is tested via the "Lethal Dose for 50%” (LD50) method - how much venom it takes to kill 50% of the test animals (usually mice).

When discussing the LD50, we must also consider the route of injection:

Subcutaneous

Under the skin. These bites are the most applicable to actual snakebites.

Intramuscular

Into the muscle. Very large specimens of Gaboon Vipers, Puff Adders, Rhino Vipers, Rattlesnakes, Bushmasters, and South American Lanceheads (also called Fer-de-lances) are about the only snakes capable of delivering this type of bite.

Intravenous

In a vein. These bites are extremely rare and very, very unfortunate, as many of those are rapidly fatal.

Intraperitoneal

Directly into the body cavity. These bites are even rarer for humans.

The dangerous effect of snake venom on humans is well known, but there are also many medicinal uses of snake venom, this specialized saliva has been used in medical situations across the globe:

Excessive bleeding

A blood-clotting protein in Taipan venom has been found to stop excessive bleeding during surgery or after major trauma.

Stroke

Components of Malayan Pit Viper venom has shown potential for breaking blood clots and treating stroke victims.

Neurological diseases

Enzymes from cobra venom may be instrumental to finding cures for Parkinson's disease and Alzheimer's disease.

Cancer (various types)

An enzyme derived from copperhead venom could be used for treatment for breast cancer.

Aging

Yes, some are even used in a commercial wrinkle cream!