This chapter aims to report the effects of physical pathology on the foraging productivity of the Yora and Shiwiar of Eastern Amazonia, and to explore the adaptive problems for human social relations posed by pathology risk. It outlines how adaptations designed to elicit behavior to mitigate these problems may operate. The Yora are a hunter/horticulturalist group of Panoan-speaking people who live in the Amazonian lowlands of southeastern Peru near the Mishagua and Manu rivers. Yora and Shiwiar engage in many types of behavior found among hunter-gatherers known ethnographically and archaeologically: they live in small kin-based communities in which some foods are shared. In a survey of injury and illness among the Shiwiar, 13 of 24 adults surveyed reported being bitten by a venomous snake at least once. Repeated periods of injury or illness can have adverse consequences for growth, life-span, cognitive function, and fertility.