Poor countries can make headway against two killer diseases by the simple, low-cost method of encouraging citizens to wash their hands with soap, according to a paper that appears in next Saturday's Lancet.
Pneumonia and diarrhoea, both caused by bacteria, are the two biggest causes of childhood deaths in the world, killing more than 3.5 million children every year.
Doctors led by Stephen Luby, of the US Centers for Disease Control and Prevention (CDC), carried out a trial in a squatter settlement in the city of Karachi.
Six hundred households were assigned to a scheme to promote handwashing.
They were given either anti-bacterial soap or ordinary soap, and were visited by fieldworkers at least once a week for a year, who distributed the soap, encouraged handwashing and recorded the state of health of household members.
Three hundred other households were "controls" - they acted as a benchmark, receiving neither soap nor fieldworker visit.
There was no difference in results between anti-bacterial or plain soap.