Hand washing with soap significantly reduces the spread of pneumonia and diarrhea, the two leading causes of death worldwide among children younger than age five. In a study funded primarily by P&G Beauty, a division of Procter & Gamble, researchers examined 900 households in squatter settlements in Karachi, Pakistan. Although the public health benefits of clean hands are clear, whether poor communities by themselves can afford to purchase soap regularly remains uncertain.

Number of pneumonia cases (per 100 person-weeks) among households that washed:

With antibacterial soap: 2.42

With plain soap: 2.20

Without soap: 4.40

Number of diarrhea cases among households that washed:

With antibacterial soap: 2.02

With plain soap: 1.91

Without soap: 4.06

Grams of soap used each day by each person in the study: 4.4

Weekly cost of soap use: about $1

Weekly income of nearly half the households: less than $15

SOURCE: Lancet, July 16, 2005