Over the past two years, medical providers across America have quietly embraced a new AI tool called OpenEvidence to help them make clinical decisions, brush up on medical knowledge and even prepare for their licensing exams. The service, a sort of chatbot for doctors, was used by about 65% of U.S. doctors across almost 27 million clinical encounters in April alone, the company told NBC News.

“Everyone is using it,” said Dr. Anupam Jena, an internal medicine physician at Massachusetts General Hospital in Boston and a professor of healthcare policy at Harvard. “Its growth really has been exponential.”

NBC News spoke with over two dozen doctors, hospital administrators, medical students and healthcare researchers from Hawaii to Maine to explore the rise of OpenEvidence. Each individual said they either used it regularly themselves or knew someone who did.

Almost two-thirds of physicians — or roughly 650,000 doctors — in the U.S. actively use OpenEvidence, while another 1.2 million use it internationally, OpenEvidence representatives said. With its quick and tailored replies, OpenEvidence has become an AI-era equivalent of consulting a colleague for their expert opinion, though the software can also write patient discharge notes and provide custom study tools for doctors’ medical exams.

“Sixty percent of all the searches are about how to make clinical decisions,” said Jena, who is currently examining 90 million OpenEvidence queries submitted since 2024 as part of a new research project. “The physicians are asking: For this particular patient, or with this profile, this condition, maybe other comorbidities that they have, what’s the right treatment?”

Yet with OpenEvidence’s skyrocketing popularity, some experts worry about potential hallucinations or incomplete answers, a lack of rigorous scientific studies on the tool’s patient impact, and the potential for doctors’ critical thinking and evaluation skills to erode with increased OpenEvidence use and dependence.

But many in the medical world see OpenEvidence as a time-saving tool that can improve patient care.

“The vast majority of our physicians are familiar with it, depending on their area of specialty,” said Dr. Jeremy Cauwels, a hospitalist and the chief medical officer for the Sanford Health system based in Sioux Falls, South Dakota.

“OpenEvidence is one of those tools that’s remarkably easy to adopt,” said Cauwels, who oversees more than 2,500 healthcare providers in the country’s largest rural healthcare system. “It’s freely available, it’s very functional on your phone, and it’s one of those things that can help you answer questions more quickly than you would be able to by any other method.”

Doctors across specialties, states and clinic sizes echoed the sentiment.

OpenEvidence is clear that its services should be used to supplement — not replace — doctors’ judgment. “While we hope you find the Services useful to you as a healthcare professional,” its terms of service say, “they are in no way intended to serve as a diagnostic service or platform, to provide certainty with respect to a diagnosis, to recommend a particular product or therapy or to otherwise substitute for the clinical judgment of a qualified healthcare professional.”

OpenEvidence also says it complies with HIPAA, the federal health privacy law, through a series of privacy protocols and protections. In April of last year, the company said that “U.S. covered entities can securely input protected health information (PHI) in accordance with HIPAA’s privacy and security standards.” However, some health systems are not satisfied with the system’s overall privacy safeguards. For example, MaineHealth currently asks its doctors to refrain from entering PHI into OpenEvidence.

Some of the doctors reached by NBC News said that they and their colleagues used the platform on their personal devices, including information such as a patient’s age, sex and previous medical history in their queries but refraining from entering names or other personal identifiers.

At its core, OpenEvidence is an AI-powered medical search engine that combs through vast databases of healthcare research to provide suggestions about clinical decisions or medication options and help highlight the latest evidence from a variety of medical fields.

OpenEvidence has also struck agreements with specialized medical organizations like the National Comprehensive Cancer Network and the American Diabetes Association to provide the latest and most relevant treatment guidelines.

Few studies have rigorously examined how OpenEvidence affects patient outcomes, largely due to how recently the tool has exploded in popularity. While OpenEvidence highlights that it scored 100% on the official United States Medical Licensing Examination, an academic study released in December found that OpenEvidence accurately answered more complex medical questions less than 45% of the time. That study has not yet been peer reviewed. (Source: NBC News)

Story Date: May 15, 2026