Auto-brewery syndrome, also known as gut fermentation syndrome, occurs when excess yeast trapped in the small intestine ferments sugars into ethanol causing drunkenness. We all have a certain amount of yeast in our gut and ideally enough good bacteria to keep the yeast in check. People with auto-brewery syndrome have elevated yeast levels which create this condition. To keep yeast in check be sure that you are eating plenty of fresh fruits and vegetables, some fermented foods like tempeh and kombucha, and taking a high-quality probiotic — especially if you must use an antibiotic.