PIP: In sub-Saharan Africa, the population of school-age children is expected to increase by 205 million during the 1990s. Mortality is low among this group, but morbidity commonly affects physical growth, school attendance, and ability to learn. Given that there are more schools than clinics and that schools collect children in one place, schools are an ideal place for health education. Training of teachers as health educators will require cooperation between ministries of health and education. Some health problems can be treated in schools. These include the presence of intestinal worms (which is assumed to warrant mass treatment if 50% or more of the smears of 30 children are infected), schistosomiasis (in which mass treatment is warranted if 30% of children report blood in their urine), and micronutrient deficiencies. Teachers can be trained to determine disease prevalence and deficiency levels and to administer treatment. Body height can be used to determine the correct dosage of praziquantel to treat schistosomes. Teachers can also be trained to detect poor vision and growth faltering and can administer iodine and vitamin A to their students as well as iron supplementation to adolescent girls. One problem with this school-based approach is that it misses children who are not enrolled in schools. School health programs, however, can achieve good coverage in a very cost-effective manner, as can be seen by the experiences of Ghana and Tanzania, where praziquantel and albendazole are administered together by teachers under the supervision of local health personnel. The low cost of all of the drugs needed to combat these diseases and deficiencies combined with the existence of the delivery system has led to identification of school health services as one of the six most cost-effective public health interventions.