ClinicalTrials.gov is a web-based resource that provides patients, their family members, health care professionals, researchers, and the public with easy access to information on publicly and privately supported clinical studies on a wide range of diseases and conditions. ClinicalTrials.gov is maintained by the National Library of Medicine (NLM) at the National Institutes of Health (NIH). Information on ClinicalTrials.gov is provided and updated by the sponsor or principal investigator of the clinical study. Studies are generally submitted/registerd to ClinicalTrials.gov when they begin, and the information on the site is updated throughout the study. In some cases, results of the study are submitted after the study ends. ClinicalTrials.gov is commonly referred to as a "registry and results database“ of clinical studies.