Obstructive sleep apnea (OSA) affects more than one billion people worldwide. Evidence suggests OSA can alter the gut microbiome (GM) and may promote OSA-associated co-morbidities, including diabetes, hypertension and cognitive problems. Researchers have discovered how OSA-related sleep disturbances affect the gut microbiome in mice and how transplanting those gut bacteria into other mice can cause changes to sleep patterns in the recipient mice.