Everyone has that one thing that completely grosses them out. Pus-filled boils, mouldy food, burping, farting, spitting, filthy public bathrooms, weeping sores, people picking their nose, people blowing their nose, people picking and flicking ... pretty much anything people do with their noses really.

Okay, maybe it's not just one thing. There are so many things in this world that have the potential to make us feel completely repulsed. But what would you say was the grossest thing in the world? That was the question posed to 2,500 people online, who were asked to take part in a survey to determine the worst thing an individual could do to make someone's skin crawl.

Researchers - who established six categories of disgust - surveyed the participants by providing them with a list of 75 potentially disgusting situations. People then rated their responses on a scale from "no disgust" to "extreme disgust", with infected wounds producing pus overall voted the most disgusting.

But the study wasn't done yet, wanting to know exactly why the things that outright horrify us are just so awful. Researchers have long-believed that disgust has an evolutionary origin and the study's results built on this theory, suggesting that being revolted is a natural reaction that protects us from people, behaviours and anything else that may pose a risk of disease.

Take poor hygiene, for example. Picking your nose and not cleaning your body increases your chances of becoming ill, therefore, most of us are sickened by it. This goes for gone off food, animals that carry illness, and wounds and lesions too, as well as people with atypical appearances and risky sexual practices.

"It shows us that disgust as an emotion evolved to make us do things that would have been good for us in the evolutionary past," said Val Curtis, professor at the London School of Hygiene & Tropical Medicine and co-author of the study. "Rather than being organized by category of infectious disease, the brain’s architecture is organized by categories of things that it’s a good idea to avoid coming into contact with."

One of the most interesting things that the study discovered was that women tend to be more grossed out by things than men, with a 12 per cent difference in their disgust scores. Experts on the study have stated that there's a chance this may have an evolutionary origin.

"On the whole men tend to take more risks," Curtis said, "because in the past men who took more risks had more offspring, while women who were more careful were able to bring up more children successfully." In addition, the research suggested that men may be less likely to be grossed out by signs of sexually transmitted diseases, and more likely to go forward with risky sexual behaviour.

So, what is your number one grossest thing in the world? I have to say, picking and flicking is up there on mine. It can only be a good thing that our bodies make us feel grossed out in order to protect us, but what's to protect our eyes when someone decides to have a fumble up their nose on the train?

Everyone has that one thing that completely grosses them out. Pus-filled boils, mouldy food, burping, farting, spitting, filthy public bathrooms, weeping sores, people picking their nose, people blowing their nose, people picking and flicking ... pretty much anything people do with their noses really.

Okay, maybe it's not just one thing. There are so many things in this world that have the potential to make us feel completely repulsed. But what would you say was the grossest thing in the world? That was the question posed to 2,500 people online, who were asked to take part in a survey to determine the worst thing an individual could do to make someone's skin crawl.

Researchers - who established six categories of disgust - surveyed the participants by providing them with a list of 75 potentially disgusting situations. People then rated their responses on a scale from "no disgust" to "extreme disgust", with infected wounds producing pus overall voted the most disgusting.

But the study wasn't done yet, wanting to know exactly why the things that outright horrify us are just so awful. Researchers have long-believed that disgust has an evolutionary origin and the study's results built on this theory, suggesting that being revolted is a natural reaction that protects us from people, behaviours and anything else that may pose a risk of disease.

Take poor hygiene, for example. Picking your nose and not cleaning your body increases your chances of becoming ill, therefore, most of us are sickened by it. This goes for gone off food, animals that carry illness, and wounds and lesions too, as well as people with atypical appearances and risky sexual practices.

"It shows us that disgust as an emotion evolved to make us do things that would have been good for us in the evolutionary past," said Val Curtis, professor at the London School of Hygiene & Tropical Medicine and co-author of the study. "Rather than being organized by category of infectious disease, the brain’s architecture is organized by categories of things that it’s a good idea to avoid coming into contact with."

One of the most interesting things that the study discovered was that women tend to be more grossed out by things than men, with a 12 per cent difference in their disgust scores. Experts on the study have stated that there's a chance this may have an evolutionary origin.

"On the whole men tend to take more risks," Curtis said, "because in the past men who took more risks had more offspring, while women who were more careful were able to bring up more children successfully." In addition, the research suggested that men may be less likely to be grossed out by signs of sexually transmitted diseases, and more likely to go forward with risky sexual behaviour.

So, what is your number one grossest thing in the world? I have to say, picking and flicking is up there on mine. It can only be a good thing that our bodies make us feel grossed out in order to protect us, but what's to protect our eyes when someone decides to have a fumble up their nose on the train?