Microbiome A large proportion of our immune system resides in the gut. Inflammasomes are host molecular complexes that sense danger and activate immune responses to food-related signals and foreign pathogens. Studies in mice have suggested that Nlrp6-ASC inflammasomes influence gut flora composition and susceptibility to obesity, colon inflammation, and fatty liver disease. Mamantopoulos et al. analyzed the microbiome of Nlrp6- or ASC-deficient mice and littermate siblings containing functional copies of the encoding genes. The study compared mouse cohorts housed in two separate animal facilities in different countries. The authors found that, in contrast to previous reports, Nlrp6- and ASC-mediated inflammasome signaling may not affect immunity or shape gut flora. Immunity 10.1016/j.immuni.2017.07.011 (2017).