We show that ethnic distances lead to worse child health outcomes by impeding access to health-related information. We combine individual level micro data from DHS surveys for fourteen sub-Saharan African countries, with a high-resolution dataset on the spatial distribution of ethnic groups at the 1 × 1 sq. km level constructed using an Iterative Proportional Fitting algorithm. We show that children whose mothers are linguistically more distant to their neighbours face higher mortality rates and are shorter in size. Linguistically distant mothers are also less likely to know about the oral rehydration product for treating children with diarrhoea.