Heartburn, and its even uglier cousin, acid reflux, can leave a person feeling incredibly uncomfortable, which is why drugs meant to treat such conditions are so popular. But, given the choice, most people would likely choose a bit of digestive discomfort over other more serious conditions like, oh I don’t know, cancer.

Apparently, that’s a choice that some will now have to consider, as the FDA is alerting heartburn sufferers that rely on the medication ranitidine — sold under the brand name Zantac — that the drugs may be tainted with a potentially cancer-causing impurity.

In its bulletin, the Food and Drug Administration explains that recent samples of ranitidine have tested positive for N-nitrosodimethylamine, or NDMA. NDMA is believed to be a human carcinogen, meaning that it’s a potential cancer-causing agent, and this impurity was discovered as part of a larger effort to spot potentially deadly ingredients in many oft-prescribed medications.

NDMA contamination has been found to be a serious problem in many heart and blood pressure medications, and the FDA has already had to force recalls of several products. That said, this bulletin is not a notice of yet another impending recall, as the FDA notes that it’s still determining how big of a risk this particular discovery poses to the public.

The FDA’s statement also notes that the levels of NDMA found in several ranitidine medications “barely exceed amounts you might expect to find in common foods.”

The FDA also emphasizes that it’s not issuing a recall at this time, and that people should keep taking their prescribed medications for the time being:

The FDA is not calling for individuals to stop taking ranitidine at this time; however, patients taking prescription ranitidine who wish to discontinue use should talk to their health care professional about other treatment options. People taking OTC ranitidine could consider using other OTC medicines approved for their condition. There are multiple drugs on the market that are approved for the same or similar uses as ranitidine.

Still, if you’re a daily user of such medications, it’s probably worth thinking about.