Summary: This report from PATH highlights the broad array of lifesaving prevention and treatment solutions for addressing diarrheal disease in the developing world. Diarrheal Disease: Solutions to Defeat a Global Killer presents scientific evidence to support strategies to scale up use of interventions including safe water, improved sanitation and hygiene, breastfeeding and optimal complementary feeding, rotavirus vaccines, zinc treatment, and oral rehydration therapy/oral rehydration solution. Additionally, the report features case studies from several organizations making a real impact with on-the-ground programs that bring these tools to the communities that need them most.