It’s a scene straight from the television show “Cops”: A man stumbling down the street and slurring his speech swears up and down that he hasn’t been drinking. A driver who fails a breathalyzer test promises she only had one beer.

Surely, these people are lying. But what if they’re not? A rare disease called gut fermentation syndrome causes people to become intoxicated without consuming alcohol. A recent article in the International Journal of Clinical Medicine describes the disease and shares a complete case study of a recent patient.

Gut fermentation syndrome likely occurs when yeast overpopulates the intestinal system. Add lots of carbohydrates to the mix by eating a big spaghetti dinner, and you’ve got a beer brewery in your belly. The yeast ferments the carbs, producing alcohol.

When the body processes all this alcohol, the results can be drastic. Blood alcohol levels can become dangerously high, up to five times the legal limit in most states for the man described in the case study. These people show all the signs of being drunk, and their breath may even smell of alcohol.

Most Western health care workers don’t know about gut fermentation syndrome, according to the recent journal article. That begs the question: How many seemingly drunk patients are actually suffering from this strange illness? And another question: Is there any way to tell the difference?

In several recent cases, cultures from the patients’ intestines grew the responsible varieties of yeast, the journal article authors reported. Antifungal medications also cleared up these cases. At least one patient took probiotic pills to help restore the gut’s normal bacterial balance.

Thankfully, gut fermentation syndrome is pretty simple to treat. And no, you shouldn’t fake having it to avoid problems with the law. That’s just brewing up trouble.