Nipple shields have become commonplace in the United States for a wide range of breastfeeding problems. This article is a summary of the current literature describing the evidence for nipple shield use. The authors reviewed all available articles on nipple shields and selected 13 studies for inclusion. The studies were organized into three categories: physiologic responses, premature infants, and mothers' experiences. This review concludes that current published research does not provide evidence for safety or effectiveness of contemporary nipple shield use.