In this clicker case study, students review and apply their knowledge of alcoholic fermentation to a rare clinical condition called auto-brewery syndrome (ABS). After “Natasha” and her husband “Greg” enjoy a pasta dinner, she later awakens with a headache, dizziness, nausea, and vomiting. Natasha has a history of recurrent urinary tract infections (UTIs) and is also pre-diabetic. In the emergency room, testing rules out COVID-19, influenza, UTIs, and pregnancy. The attending ER physician notes however that Natasha has a blood alcohol level of 0.26%, but she assures the medical staff that she has not consumed any alcoholic beverages. The ER physician recalls a similar case and orders a stool analysis to test for yeast. The results indicate an overgrowth of yeast, suggesting that Natasha is most likely suffering from auto-brewery syndrome. This case was developed for a first-year college general biology course to reinforce fermentation concepts. It is also suitable for advanced placement high school courses.