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Is There Such a Thing as Sympathetic Vomiting?

Close up of a person's eye
Image source: Liam Welch (via Unsplash)

Have you ever witnessed someone yawning and been unable to prevent yourself from following suit? Sometimes it’s hard to suppress a yawn after just hearing the sound of one. This phenomenon is often referred to as contagious yawning, and scientific studies have confirmed that it is a real thing.

A potentially scary prospect for those with emetophobia is the similar notion of sympathetic vomiting. In this article EmetoGo explains exactly what this means and why it happens, along with some useful tips on how to prevent it from occurring.

What is sympathetic vomiting?

Sympathetic vomiting (SV) is the idea that just watching, hearing or smelling someone else being sick can cause you to do the same. You may have seen it depicted in TV shows and films (some of us are still scarred from watching that Stand By Me scene—emetophobes, you have been warned).

Some real life episodes of mass vomiting outbreaks have also noted this phenomenon as a factor. For example, when two dozen school children in North Carolina experienced a sudden outbreak of sickness in 2019, public health officials put it down to a nausea-inducing combination of “fruit-flavored concentrate, spicy food and ‘sympathetic vomiting.’”

Why does it happen?

As is the case with a lot of bodily responses, there are a range of explanations for why SV may occur. Let’s take a look at 3 significant factors.


It has been proposed that sympathetic vomiting is evolutionary in nature as it may have been a mechanism to protect our ancestors from illness or death by poisoning. Early man lived in small communities that tended to eat as a group. If one member of the group vomiting caused the rest to do the same, it could potentially save their lives in instances where the food they were consuming was spoiled or not fit for human consumption.

In this sense, SV can be seen as a survival trait that, to this day, some people have not unlearned. Indeed, sympathetic vomiting is still witnessed in animal societies in the wild, including those of apes.

Personality type

Man in white jumper yawning
Image source: Sander Sammy (via Unsplash)

Another explanation for SV is that it affects those who have high levels of empathy. This is slightly confusing as sympathy and empathy are not the same thing—the former means to feel sorry for another person, whereas the latter refers to the ability to understand and share the emotions that another person is experiencing.

While there are very few studies that explore sympathetic vomiting, we can glean some information from research on contagious yawning. A 2013 study by Gupta and Mittal discovered that those with high levels of empathy were much more likely to exhibit contagious yawning. They also found that rates of contagious yawning increased when the relationship between the observer and the yawner was close in nature: “The social bond associated with empathy affects the yawn contagion in humans in terms of occurrence, frequency and latency.”

A 2011 study by Norscia and Palagi also found that social relationships had a significant influence on rates of contagious yawning, further confirming that empathy plays a key part in such mechanisms:

“The importance of social bond in shaping yawn contagion demonstrates that empathy plays a leading role in the modulation of this phenomenon. Not only is contagion greater between familiar individuals, but it also follows an empathic gradient, increasing from strangers to kin-related individuals.”

If we apply these ideas to vomit, it suggests that SV may occur when empathetic people observe another person throwing up, particularly if it is somebody known to them. They then experience the same feelings of disgust or nausea and follow through with the same bodily response.

Biological mechanism

The empathy component of contagious yawning and (presumably) SV is not just an emotional response, it is also a biological process that has been observed. Scientists propose that emotionally evolved people have ‘mirror neurons’ that enable them to feel the emotions of other people. As explained in a 2008 study by Nummenmaa et al:

“Emotional empathy facilitates somatic, sensory, and motor representation of other peoples’ mental states, and results in more vigorous mirroring of the observed mental and bodily states than cognitive empathy.”

Norscia and Palagi also observed these biological processes when studying contagious yawning:

“Perceiving other persons yawning activate a complex network of brain regions related to motor imitation, social behavior, and empathy, which also involves both sensorimotor cortices and limbic and para-limbic structures (sic).”

While such research provides us with potential explanations for sympathetic vomiting, we must keep in mind that we cannot necessarily apply research based on yawning to other bodily functions.

Are people with emetophobia sympathetic vomiters?

If not already aware of it, the notion of sympathetic vomiting could strike fear in the heart of a person with emetophobia. Thankfully, if it isn’t a behaviour you’ve already noticed about yourself, it is highly unlikely that you possess this trait.

While it is common for emetophobes to fear that being near sick people will also make them sick, this is usually down to anxiety about being in close proximity to a sickness bug, or sheer disgust at the act itself. That being said, worries about sympathetic vomiting may be one of the reasons that certain emetophobes have an intense fear of witnessing other people being sick.

You can gain further comfort from the fact that, just because sympathetic vomiting is likely to be a real phenomenon, it does not mean that it is common. If this were the case, numerous job roles (nursing, teaching, nannying, etc.) would be out of the question for huge swathes of people. Furthermore, there would be much higher rates of mass vomiting incidents, like the one mentioned earlier. Fortunately, such episodes remain fairly rare.

Tips to prevent sympathetic vomiting

Woman in sunglasses sat on sand next to sign reading 'This is my happy place' and multi-coloured life ring reading 'Life's a beach'
Image source: Artem Beliaikin (via Unsplash)

If you do experience sympathetic vomiting, the following tips can help you stop it from happening:

  • Cultivate a detailed “happy place” that you can go to mentally when confronted with someone throwing up.
  • Avoid films and other forms of media that may depict vomiting. Sites like DoesTheDogDie have helpful lists for this.
  • Learn relaxation techniques that can help you to calm down and focus on your breathing during potentially triggering situations.
  • If you find yourself gagging, put earphones in and listen to music or white noise to switch your focus and override the reflex.
  • Always carry mints and something that smells pleasant (like lavender) so that you can distract your senses, should somebody in your vicinity get sick.