Diarrhoeal diseases killing millions of babies around the world each year could be prevented by providing good toilets, lavatories or latrines: especially when designed with full participation of local communities so that they are suitable and get used. That's according to Sandy Cairncross, Professor of Environmental Health at the London School of Hygiene and Tropical Medicine - co-author of a series of articles just published in the on-line journal: Public Library of Science - Medicine. He discusses the importance of good sanitation and water supplies.