TikTok is full of cold-fighting tips, from red onion water to marshmallows. But do they work?

Are marshmallows good for warding off a cough? What to know. (Getty Creative)
Are marshmallows good for warding off a cough? What to know. (Getty Creative)

TikTok has turned into a go-to spot for users to share cold-fighting tips and tricks — some of which are backed by solid scientific research, and some of which definitely fall into the category of "dubious social media trend." Got a cough? Try stuffing a marshmallow in your mouth. Under the weather? Stick a potato in your sock, TikTokers tell you.

But while there are indeed household staples that are genuinely proven to help prevent or treat illnesses, some of these online remedies don't work. How can you separate the helpful from the useless? Here, experts weigh in on social media's advice for curing what ails you.

Drinking onion water

It may sound gruesome, but some TikTokers swear that boiling red or yellow onions in water and drinking it took them from sick as a dog to back on their feet in a matter of days. (The state of their breath, on the other hand? Well...)

Dr. Sameera Davuluri, assistant professor in the University of Alabama at Birmingham's department of family and community medicine, tells Yahoo Life that there is no evidence that drinking this onion concoction helps with a cold. If you’re not a fan of the taste of onion water, you can skip this one — especially if your gut is sensitive to onions (such as those on low FODMAP diets).

That’s not to say it’s totally ridiculous to think onion water may support your body. Drinking plenty of fluids is one scientifically backed approach to manage symptoms and keep yourself hydrated. Red onions also have some healthy properties which can support your overall well-being, like vitamin C, calcium, phosphorus, potassium and folate, says Davuluri. Plus, they also contain organosulfur compounds and the flavonoid quercetin, which has potential anti-inflammatory properties.

Making immunity cubes

Lots of TikTokers swear by their own personal health elixirs, which typically include things like orange juice mixed with ginger, honey and turmeric. While some stores sell pre-packaged versions of these drinks, other people make their own and freeze the liquid in an ice tray to make what they call “immunity cubes,” which they can use next time they are sick.

Dr. Niharika Khanna, a family physician and professor at the University of Maryland Medical Center, tells Yahoo Life that these ingredients won’t hurt you, and that honey, in particular, can coat your throat when it is sore or when you have a cough. Turmeric and ginger, meanwhile, have antioxidant properties, while oranges and other citrus fruits like lemon contain vitamin C.

While these kinds of beverages won’t hurt you, and may cause some temporary relief, Khanna says that it’s important to understand that there is no recommended medical treatment for a cold, and these concoctions should not be considered an official treatment.

Putting a potato in your sock

Can putting a piece of potato in your sock cure your cold? No, says Davuluri — even if the potato turns black, which some TikTokers swear is due to the virus leaving your body. “This is not true and has no health benefit,” she explains. “The black color is due to an oxidative reaction that occurs when a raw potato is exposed to air.”

If you want to get the most benefit from potatoes, you can try something a bit more fun: eating them! Potatoes are high in vitamin C, which can support immune function.

Eating garlic by the spoonful to ward off a cold

Garlic is delicious in Italian dishes, less so when eaten raw as a clove, as some TikTokers do to fight off a cold. Khanna says that while it’s not taught in modern Western medicine as a treatment, garlic has been associated with lower cholesterol levels as well as a slew of other health benefits, though more research is needed. Dr. Anant Vinjamoori, chief medical officer of Modern Age, tells Yahoo Life that “garlic possesses antimicrobial properties,” but warns that “consuming a spoonful alone is unlikely to provide significant relief from a cold.”

If you’re a garlic fan, go for it, but also remember that garlic, like onion, can be harsh on the gut for some people. You don’t want a sniffly nose and sour stomach.

Eating a marshmallow to stop a cough

A TikToker went viral for one sweet sore throat fix: She claimed that her doctor told her a jumbo marshmallow before bed could alleviate symptoms of her long-lasting cough. The reason, the doctor said, was because gelatin, much like honey, coats the throat. While there’s no scientific research to support this claim, there is a reason why the doctor might have suggested it.

The herb marshmallow root has long been associated with coating the throat, due to the presence of mucilage, a thick, gelatinous substance with adhesive properties known for its ability to provide a soothing and protective effect. The ancient Egyptians first combined marshmallow root extract with sugar and water to create marshmallows; however, modern versions now substitute the root for gelatin. (Vegan marshmallows use items like agar or pectin in place of gelatin, which is made of crushed animal bone.)

If you feel like a marshmallow before bed helps your cough, there’s no reason not to consume one, assuming you enjoy the taste. However, you may be better off trying something with marshmallow root (or just go with tried-and-true honey).

The bottom line

Dr. Anne Liu, a specialist in infectious diseases at Stanford Health Care, tells Yahoo Life that none of the TikTok trends are proven to prevent or treat a respiratory viral infection. While a healthy immune system helps to fight off these infections, you don’t need any special tricks in order to keep yourself healthy. She recommends sticking to the basics, like “getting enough sleep, getting regular exercise, reducing stress and eating a well-balanced diet that includes a variety of fruits and vegetables.”