Geophagy, the habit of eating soil, has its human origins in tropical Africa from where the practice migrated to become almost a universal phenomenon. Today, geophagy has the widest distribution amongst the world's poorer or more tribally-orientated people. Deliberate soil consumption is, therefore, still common in the tropics, yet geophagy remains largely an under-reported and misunderstood practice. The aetiology of soil eating is manifold, though the causal link between geophagy and the regulation of mineral imbalances still remains to be confirmed. Nevertheless, soils have the potential to be an important source of mineral nutrients, especially iron, to geophagists.