The Trusted Provider of Medical Information since 1899honeypot linkMSD MANUALSThe Trusted Provider of Medical Information since 1899The MSD Manuals are a comprehensive medical information source covering thousands of topics in all fields of medicine. They are offered as a free public service to health care professionals and the general public.Choose the version that best meets your needsMSD ManualProfessional VersionFor Medical Professionals and Students, more advanced content and featuresI’m a medical professional or student.Go To Professional Version 1000s of Topics “How-To” Videos Numerous Photos Clinical Calculators Quizzes 3D Models News and Editorials MSD ManualConsumer VersionFor the General Public, information that is clear and easy to understandI’m a patient, parent or caregiver.Go To Consumer Version 1000s of Topics 100s of Animations Numerous Photos and Illustrations Self-Assessment Tools Quizzes 3D Models Common Medical Tests MSD Veterinary ManualVeterinary ManualFor Veterinary Professionals and Students, the world's most widely used veterinary referenceI’m a vet or pet owner. Go to Veterinary Manual 1000s of Topics Dozens of Species Numerous Videos and Photos Clinical Calculators Quizzes Reference Guides Case Studies, News and Editorials Our mission is simple: The Manuals, first published in 1899 and now known as MSD Manuals outside the United States and Canada, are one of the world’s most widely used medical information resources. The Manuals are committed to making the best current medical information accessible to health care professionals and patients on every continent. We believe that health information is a universal right and that every person is entitled to accurate and accessible medical information. We have a responsibility to protect, preserve and share the best current medical information to enable more informed decisions, enhance relationships between patients and professionals, and improve health care outcomes around the world. That’s why we are making the Manuals available for free in digital form in multiple languages to professionals and patients around the world.MSD and the MSD Manuals At MSD we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. First published in 1899 as a small reference book for physicians and pharmacists, The Manual grew in size and scope to become one of the world's most widely used comprehensive medical resources for professionals and consumers. As The Manual evolved, it continually expanded the reach and depth of its offerings to reflect the mission of providing the best medical information to a wide cross-section of users, including medical professionals and students, veterinarians and veterinary students, and consumers. Learn more about our commitment to Global Medical Knowledge. MSD MANUALSAboutDisclaimerPermissionsPrivacyCookie PreferencesTerms of useLicensingContact UsGlobal Medical KnowledgeVeterinary ManualMobile AppsCopyright© 2026 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. All rights reserved.
