Due to dietary modifications including the intake of cereals, vegetables and the frequent use of soy milk instead of breast milk, children in developing countries with diarrhea frequently suffer from zinc deficiency. Furthermore, diarrhea leads to excess zinc losses. Beside low energy intake zinc deficiency contributes to continued diarrhea, which in turn accounts for half of the deaths from diarrhea in children. Zinc supplementation leads to accelerated regeneration of the mucosa, increased levels of brush-border enzymes, enhanced cellular immunity and higher levels of secretory antibodies. In addition, in stunted children zinc supplementation results in enhanced catch-up growth via higher levels of insulin-like growth factor-I. Growth retardation is closely related to the risk of diarrheal diseases in children. These pathophysiological conclusions are supported by several controlled clinical traits which have provided evidence that zinc supplementation results in significant reduction in the risk of continued diarrhea. However, it remains to be clarified whether these benefits are attributable to pharmacological effects or if they can be related to the correction of an underlying deficiency state.