If you’re a fan of flavored e-cigarettes, especially flavors like cherry, you may want to heed the warnings of a recent study. According to a report from HealthDay News, scientists suggest that the flavor chemicals added to electronic cigarette cartridges can cause acute irritation in the airways.

According to Maciej Goniewicz, a professor of oncology at Roswell Park Cancer Institute in Buffalo, NY, “It might be the case that if the user of an electronic cigarette experiences some side effects, like coughing, it might be attributed to the flavorings.” Scientists have identified a key chemical, benzaldehyde, as the culprit behind the health risks posed by e-cigs.

Benzaldehyde is a commonly used chemical found in flavored foods and cough syrups. It is completely safe to eat, and creates a flavor reminiscent of cherries or almonds. When inhaled through an e-cigarette, however, scientists found that the chemical was present in concentrations sufficient to cause significant irritation of the airways. While the concentration in most e-cigs is still over 1,000 times lower than the maximum workplace exposure level recommended by federal agencies.

So are e-cigarettes still the safer alternative to smoking traditional tobacco products? According to the Smoke-Free Alternatives Trade Association, an industry support group for e-cigarette companies, electronic vapor cigarettes are still a better alternative than normal cigarettes. “Let’s not lose sight that vaping presents substantially less risk than combustion cigarettes, which expose smokers to over 7,000 chemicals including more than 60 known or suspected carcinogens,” said the group.

Not all doctors feel the same, however. According to Dr. Norman Edelman, the senior scientific advisor with the American Lung Association, the recent study reveals how little scientists actually know about e-cigs and their effects on the body. “To me, it’s another piece of evidence that we don’t know what’s in those things. It’s terribly important that the U.S. Food and Drug Administration use its power to regulate them. The first thing they can do is find out what is in them.”

The recent study, published in the journal Thorax, examined 145 different e-cigarette cartridges. Scientists found that benzaldehyde was present in three out of four vapor cartridges tested, and the flavors with the highest levels were cherry-flavored products.

A press release describing the details of the study can be found here.