This study evaluates the economic consequences of the successful eradication of hookworm disease in the American South. The hookworm-eradication campaign, initiated around 1910, was driven by the discovery that hookworm was a major cause of health problems in the region and a donation by John D. Rockefeller. The Rockefeller Sanitary Commission (RSC) surveyed infection rates and found that 40% of school-aged children were infected. The RSC then sponsored treatment and education campaigns, leading to a substantial reduction in hookworm disease. The study uses the cross-area differences in pre-treatment infection rates to identify the effect of the eradication campaign. Areas with higher infection rates experienced greater increases in school enrollment, attendance, and literacy after the intervention. The results are robust to controlling for various factors, including crop prices, policy changes, and malaria eradication. No significant contemporaneous results are found for adults, who should have benefited less from the intervention. Long-term follow-up indicates a substantial gain in income for those exposed to the eradication campaign. The study also finds evidence that eradication increased the return to schooling. The analysis uses data from the 1910 and 1920 censuses and includes controls for health, education, and demographic factors. The results suggest that the reduction in hookworm disease had a significant positive impact on human capital, particularly in areas with high pre-treatment infection rates. The study also examines racial differences in the effects of the eradication campaign, finding that the impact was more pronounced for blacks. The findings highlight the importance of public health interventions in economic development.This study evaluates the economic consequences of the successful eradication of hookworm disease in the American South. The hookworm-eradication campaign, initiated around 1910, was driven by the discovery that hookworm was a major cause of health problems in the region and a donation by John D. Rockefeller. The Rockefeller Sanitary Commission (RSC) surveyed infection rates and found that 40% of school-aged children were infected. The RSC then sponsored treatment and education campaigns, leading to a substantial reduction in hookworm disease. The study uses the cross-area differences in pre-treatment infection rates to identify the effect of the eradication campaign. Areas with higher infection rates experienced greater increases in school enrollment, attendance, and literacy after the intervention. The results are robust to controlling for various factors, including crop prices, policy changes, and malaria eradication. No significant contemporaneous results are found for adults, who should have benefited less from the intervention. Long-term follow-up indicates a substantial gain in income for those exposed to the eradication campaign. The study also finds evidence that eradication increased the return to schooling. The analysis uses data from the 1910 and 1920 censuses and includes controls for health, education, and demographic factors. The results suggest that the reduction in hookworm disease had a significant positive impact on human capital, particularly in areas with high pre-treatment infection rates. The study also examines racial differences in the effects of the eradication campaign, finding that the impact was more pronounced for blacks. The findings highlight the importance of public health interventions in economic development.