A new study reports that a strain of intestinal-dwelling yeast may exacerbate Crohn's Disease, and blocking the fungus from causing problems in the gut could alleviate the symptoms of inflammatory bowel disorder in some patients. Approximately 1.6 million Americans currently live with inflammatory bowel disorders (IBD), and as many as 70,000 new cases are diagnosed every year. No cure exists for IBD, though many patients manage their symptoms with anti-inflammatory drugs. While several studies have illuminated links between intestinal bacteria and IBD, scant attention has been paid to the other types of microbes living in the gut, even though almost 70% of Crohn's Disease (CD) patients are predisposed to mount immune reactions against yeast. Here, Tyson Chiaro and colleagues demonstrated that a strain of Saccharomyces cerevisiae aggravated intestinal damage in mouse models of colitis. The researchers determined that the yeast caused the rodents to produce elevated amounts of uric acid in their intestines. They gave yeast-colonized animals allopurinol (a clinical drug used to reduce uric acid), which reversed intestinal disease. To determine if yeast might cause similar effects in humans, the scientists examined serum from 168 healthy volunteers and observed a positive correlation between uric acid levels and circulating antibodies against S. cerevisiae. Testing CD patients for uric acid and immune responses to yeast could inform more targeted therapeutic interventions, the authors say.