Here's Why You Shouldn't Swallow Your Own Blood

Ever get a paper cut and instantaneously stick the finger in your mouth? You can admit to this — it's natural, according to Dr. Chris Smith on the Naked Scientists website. Anytime humans injure themselves the reflex is to stimulate the nerve cells in order to feel better. So if you knock your arm on a wall, you might rub it, and if a finger is sliced or you bust a lip, the automatic reactions work in a similar fashion.

Sucking on a cut finger will remove any foreign matter, too, taking it right down to your stomach where its acid destroys it (although a better method might include a good wash with soap and water, and applying an antiseptic). Swallowing a little bit of pathogen-free blood shouldn't harm you — say, a teaspoon or so. So don't worry about the odd nosebleed or tooth extraction that leeches blood into your digestive system.

Be careful, though, if the bleeding becomes severe and you keep ingesting it. Swallowing too much of your own blood can bother the stomach — so much so it might induce vomiting. Instead of making the situation better, this can also worsen the bleeding, according to the University of Michigan Health website. Rather than swallowing the blood, it is better to spit it out in a sink or receptacle.

Some believe that drinking human blood can help certain conditions, such as kidney disease or bleeding disorders, but no current research supports that claim. Blood transfusions can help some medical situations, but they work much differently than ingesting blood, starting with a sanitary intravenous (IV) line feeding into your veins.

When you drink blood it goes directly into the stomach, then moves to the small intestine before hitting your bloodstream. Your body can't digest blood like it does food, according to Healthline, which is why it can irritate the stomach so badly.

Drinking blood can also risk a condition known as hemochromatosis, where the body has too much iron in it. While this is mostly caused by genetics or other underlying conditions, human blood does have copious amounts of iron, and someone who consumes too much of it could reach toxic levels in their body. This could lead to all kinds of problems, from kidney disease to blood problems to nervous disorders, according to Live Science. 

So fans of "Twilight" and other vampire sagas should just say no to blood as a food source. At best, you'll have a stomachache, and, ultimately, doing so could be deadly.