Vomit Myths That Have Been Debunked By Science

Vomiting is not something that people like to discuss often, in fact for those with emetophobia, even thinking or talking about the subject can cause them to throw up. However, there are a few assumptions about vomiting that are simply not true, and believing these myths can be dangerous in some cases. Vomiting is the body's reaction to something not being right, and understanding why your body is giving up your lunch could help get to the root of the problem.

It is easy to be alarmed when you vomit, but that doesn't necessarily mean that something serious is going on. Emesis, the process of vomiting, tends to happen in three stages. First is nausea, where you have the signature feeling of thinking you will throw up, though often you do not. Then retching, where your mouth and throat make noises and motions related to vomiting, often as you run to the toilet in a panic. Finally, the contents of your stomach will appear magically and disgustingly from your mouth as the muscles in your digestive system contract to push everything upward.

Even though vomiting is thoroughly unpleasant, it can happen for fairly minor reasons, and doesn't always require a sick day or a trip to the doctor. Indigestion, migraines, and even stress can all cause vomiting, and in pregnant women especially, even a strong smell can trigger the response. If vomiting is short-lived and there are no other concerns surrounding it, there is often no need for treatment, but it is important to be aware of myths surrounding emesis, so that you can take action if appropriate.

It is natural to assume that the cause of vomiting always begins in the stomach; the phrase "sick to the stomach" even tells us so. But vomiting has many triggers, and the process originates in the nervous system and just happens to culminate with the contents of your stomach lurching upward.

The process of vomiting begins in the chemoreceptor trigger zone which is part of the brainstem, found in the medulla. Its job is to detect chemicals in the blood and trigger the vomiting response in order to expel them. While sometimes signals do come from the digestive system, if you have eaten a dodgy curry or ingested poison, other stimuli from your environment can also trigger a reaction, including for some people, the sight, sound, or mention of someone else throwing up.

In the case of motion sickness, stimuli from outside the body get mistranslated by the brain, particularly in situations such as sitting in a car, where your body is not physically moving, but your eyes tell your brain that it is. This causes the brain to trigger the vomiting reflex unnecessarily, which can cause nausea followed by vomiting. Virtual reality headsets can cause a similar phenomenon, where movement is perceived without physical motion. While vomiting always involves the stomach as the last step, the trigger for the process often starts somewhere else entirely.

When you throw up a meal you ate recently, it is logical to assume that it must be the cause of the vomiting, especially since the tastes and smells of the meal may be detectable as it makes its way out of your system. While it could be the case that your latest meal is the culprit, the science is not quite so straightforward.

According to the Centers for Disease Control and Prevention (CDC) the incubation period for a food causing vomiting varies significantly, from just 30 minutes in the case of Staphylococcus aureus food poisoning, with deli meats and sandwiches being the biggest culprits, to two weeks if the illness comes from Listeria. This broad range of timescales for food-borne illnesses means that anything you ate in the last fortnight could be responsible for making you throw up, and may require a little detective work on your part.

If vomiting and the usual associated symptoms such as stomach cramps and diarrhea are the only symptoms you have, a simple case of staph poisoning could be to blame, and should clear up on its own within a day or two. Bear in mind that the CDC recommends staying at home for 48 hours once vomit and diarrhea symptoms stop. However, if your bouts of vomiting are accompanied by fever, stiff neck, red-colored stools, or slurred speech, a more dangerous pathogen such as Salmonella or Botulism could be to blame, and seeking medical advice is recommended.

It seems logical that if something poisonous has found its way into your system, you should try to get it out as quickly as possible, but this is not the latest advice. In the past, individuals were encouraged vomit out suspected poisons, and parents were even told to keep an emetic in the house to induce vomiting in children if ingesting poison was suspected. However, the official guidance is now to contact poison control and wait for medical advice.

One of the issues with inducing vomiting is that it can cause further damage, depending on what has been ingested. If a corrosive substance such as bleach or a strong acid has been consumed, the product can cause burns on the way back up as well as during ingestion, causing serious discomfort and damage to the sensitive tissues of the esophagus and throat. Another issue with deliberately inducing vomiting is that either the vomit or the toxin can end up in the lungs, potentially causing even more serious health implications than the original poison. Aerated liquids that froth such as shampoo or liquid soap are particularly prone to this.

One of the simplest reasons that vomiting is not advised after poison ingestion is that it isn't very effective. If someone believes that vomiting has removed the poison from their system, they may be less likely to seek medical help. A study in 2003 found that use of ipecac — an emetic medication previously recommended for children — did not improve outcomes for cases of poison ingestion.

We all know that taking things easy during a drinking session is the sensible thing to do, drinking a glass of water between each drink and sipping slowly on our preferred tipple. In practice, it doesn't always happen that way, and one widely-held myth is that vomiting can clear out the alcohol and help prevent a hangover, or even allow you to drink even more. This is not true, and believing this myth can lead to risky behavior around alcohol.

When you drink alcohol — with a standard drink being around 12 ounces of beer or 1.5 ounces of vodka or whiskey — it is absorbed into your bloodstream within around 10 minutes. Forcing yourself to vomit does absolutely nothing to the alcohol which has already made its way into your blood, and is therefore having an intoxicating effect. Instead, it may make the individual feel better than they did, allowing them to continue drinking in excess on a now empty stomach, which means alcohol will be absorbed even more quickly. In effect, tactical vomiting while drinking could end up causing a worse hangover the following day, if more alcohol is consumed after the vomiting incident.

Inducing vomiting while drunk can have dangerous repercussions, including a form of pneumonia if acidic vomit enters the lungs accidentally. In extreme cases this can be fatal. Even in the best case, vomiting will further dehydrate you on top of the effects of the alcohol, leaving you feeling rough the next morning.

Seeing blood in vomit is always going to be alarming, but there is a belief that you can tell how worrying it is from the color. Hematemesis, the process of vomiting blood, is often either bright red or dark brown, but both can represent something serious that needs medical attention.

Coffee ground emesis is vomit that is dark brown or almost black, and looks like coffee grounds. Many people think this is less concerning than bright red vomit, as it represents old blood rather than fresh. However, its presence means that there has been bleeding somewhere internally, and can still be a sign of something sinister. The dark color means that the bleeding has stopped, at least temporarily, but it also means that there has been a bleed that could very well return. In a 2018 study researchers found that bloody emesis was not associated with higher rates of severe bleeding or mortality compared to coffee ground emesis. 

Possible causes of dark brown vomit include a tear in the esophagus, a bleeding ulcer, or even cancer, all of which a medical professional would take very seriously. While fresh, bright red blood may look like more of a concern, any blood in vomit is an acute medical situation and should be investigated appropriately.