Your Cough Syrup Probably Isn’t Doing Anything

There’s nothing like reading about the treatments of yore to make you grateful for modern medicine: Just over a hundred years ago, people were using bedbugs as a cure-all, wearing electroshock belts to treat impotence, and putting all kinds of unsavory ingredients in their medicines. “If you were born in the 1800s,” a recent video from the American Chemical Society notes, “your old-timey cough syrup might have consisted of morphine, alcohol, cannabis, chloroform, or even heroin.”

These days, cough medicine contains none of those things. Instead, most contain one of these active ingredients: the chemical dextromethorphan, which suppresses the brain’s signal to your body that it should cough; expectorants, which loosen up the mucus in your lungs; decongestants, which shrink the blood vessels in the nose to help clear you out; and antihistamines, which cut down on mucus production and soothe swollen tissues in the throat.

The problem is, as the same American Chemical Society video notes, none of those things really work, either:

The researchers behind the video analyzed several different reviews on the effectiveness of cough medicine, none of which came down on the medicine’s side — all were inconclusive at best, with several making the case that it just didn’t work. One such review, from the health research group Cochrane, analyzed 29 studies encompassing nearly 5,000 people, ultimately concluding only that no conclusions could be drawn: “We found no good evidence for or against the effectiveness of OTC medications in acute cough,” the authors wrote. Another paper, published in the journal BMJ in 2002, looked at results from more than 2,000 patients across 15 clinical trials; the researchers found “conflicting evidence” for all categories of medicine other than antihistamines, which weren’t any more effective than a placebo.

The good news is that a garden-variety cough will eventually go away on its own. In the meantime, there are some other ways to speed up the process: Taking a hot shower and drinking plenty of fluids both help with decongesting, while sucking candy can stimulate the production of extra saliva to ease sore throats. And if you’re convinced that cough medicine really does work for you (and you’re very careful not to take too much!), full speed ahead — after all, the placebo effect can be a powerful thing.

Your Cough Syrup Probably Isn’t Doing Anything