We’ve all seen the words “complementary,” “alternative,” and “integrative,” but what do they really mean? This fact sheet looks into these terms to help you understand them better and gives you a brief picture of the mission and role of the National Center for Complementary and Integrative Health (NCCIH) in this area of research. The terms “complementary,” “alternative,” and “integrative” are continually evolving, along with the field, but the descriptions of these terms below are how we at the National Institutes of Health currently define them. Complementary Versus Alternative According to a 2012 national survey, many Americans—more than 30 percent of adults and about 12 percent of children—use health care approaches that are not typically part of conventional medical care or that may have origins outside of usual Western practice. When describing these approaches, people often use “alternative” and “complementary” interchangeably, but the two terms refer to different concepts: If …