The World Health Organization said Friday the sale of useless or potentially dangerous drugs is hampering its worldwide campaign against the most common causes of death among children.

A WHO statement said an estimated 8 million children die each year of diarrhea and acute respiratory infections.It said at least $1 billion is wasted each year on "inappropriate treatment" of the two diseases, neither of which need be major killers. Together, the afflictions are blamed for causing more than half of all deaths of children under five years of age, WHO said.

It cited "widespread marketing of anti-diarrheal drugs and cough and cold remedies that are either useless or potentially dangerous," in addition to "inappropriate marketing of breastmilk substitutes and other unnecessary infant foods."

"Purchasing any of these products wastes the scarce resources of families and impoverished nations alike," WHO said.

Dehydration, which causes most diarrhea deaths, can be inexpensively treated with rehydration salts, it said. Death from pneumonia can be prevented with an appropriate antibiotic, "in most cases a low-priced oral formulation."