Let’s say you are at your favorite restaurant and you have just ordered a bowl of soup. You grab your spoon and when you have just begun to dive into it, you spot a strand of hair. You have these options: send the soup back to the kitchen, pick out the hair and eat it anyway, or just slurp down the soup with hair in it. But what will happen to your body if you swallow a hair strand?

In the latest video of SciShow’s “What Happens When You Swallow Hair?” Michael Aranda explains that eating a single strand of hair probably won’t do much harm. The only scenario in which hair would pose a health threat is when you eat a whole clump, as it could form a giant hairball in your stomach. Well, in your soup, there’s only a single strand of hair. It is possible that stowaway bacteria, which can upset the stomach and cause diarrhea, might try to hitch a ride on a strand. Although it’s pretty unlikely, a small amount of staph bacteria on a strand of hair would definitely give you gastrointestinal problems. But so far, the FDA has not received any reports of people getting ill from ingesting hair found in food.

The hair is made up of a densely packed protein called keratin. Humans are not capable of breaking down keratin, because to do so, it has to be treated at very acidic and alkaline conditions at a temperature of over 100 degree celsius for a long duration. However, in the human’s digestive system, such conditions do not exist. So, small amounts of hair would just pass right through your body, along with everything else you can’t digest.

“It happens to cats all the time,” says Michael. “Cats also can’t digest their hair — or in this case, fur — and whatever doesn’t pass through their digestive systems builds up in their stomachs as a firm, dense, hairball. Eventually, most cats are able to vomit up hairballs before they get too bad.”

Ingesting a large volume of hair over a long period of time could lead to formation of a firm, dense, hairball, called trichobezoars, in your stomach which could cause severe abdominal pain and other symptoms.

There has been a report of an 18-year-old Chicago girl who was suffering from stomach pain, vomiting and losing at least 18 kg over a period of five months. But later, gastrointestinal endoscopy revealed a giant hairball blocking her stomach. Upon questioning, the girl said that she had had a habit of eating her hair for many years. This disorder where one is compelled to eat his or her own hair is called trichophagia. Also, in the most extreme cases, there is a condition known as Rapunzel Syndrome, which the tail of the hairball can reach down into the small intestine.

So, is hair in food a health risk? Not really. But to be safe, if you see a strand of hair on your food, just send it back.