Two proteins ensure that cells can take up iron when needed. If both control proteins are switched off in mice, the animals develop severe anemia, as expected. Surprisingly, at the same time a cell type of the innate immune defense, the neutrophils, also dramatically decreases. Iron deficiency, a known defense mechanism against infectious pathogens, is a double edged sword, as it simultaneously curbs the defensive power of an important arm of the innate immune system.