Natural Standard is an international research collaboration that aggregates and synthesizes data on complementary and alternative medical therapies, such as herbs and dietary supplements. Information presented is evidence-based, consensus-based, and peer reviewed. Natural Standard is a full-text source, and contains references to the primary literature. The quality of available scientific evidence for each entry on the use of a therapy for specific medical conditions is graded A to F (strong positive to strong negative evidence). Natural Standard also includes a variety of tools, such as nutrition labels and calculators, and interaction checkers.