Whenever I’ve been sick for more than a few days, I start to get really tired of coughing. So I trudge over to the drug store, stare at the long aisle of cough medicines, and eventually pick one out. It never seems to do much good, though. So the next time I try a different one. But none of them ever seems to do much good. What’s up with that? R. Morgan Griffin explains why I’ve had so much trouble finding a cough medicine that works:

“We’ve never had good evidence that cough suppressants and expectorants help with cough,” says Norman Edelman, MD, chief medical officer at the American Lung Association. “But people are desperate to get some relief. They’re so convinced that they should work that they buy them anyway.” ….No new licensed cough treatment has appeared in more than 50 years — and the evidence for older drugs is not strong. A 2010 review of studies found that there is no evidence to support using common over-the-counter drugs for cough. This includes cough suppressants, such as dextromethorphan, or expectorants such as guaifenesin, which are supposed to loosen up mucus in the airways. In 2006, the American College of Chest Physicians surveyed a number of cough medicine studies from the last few decades. It found no evidence that these medicines help people with common coughs caused by viruses. It’s important to understand that these studies have not proven that cough medicines don’t work. Rather, they’ve just found no proof that they do. It’s always possible that further studies could show that they help.

Anything is possible! But apparently it’s not just me. This stuff just doesn’t help much. If it’s been working for you thanks to the placebo effect, I apologize for telling you all this.