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The $15 billion ad-powered AI startup your doctor may already be using
OpenEvidence is booming despite questions about accuracy and ads.
Nearly two-thirds of US doctors are turning to an AI-powered search engine to make patient decisions, propelling a little-known tech startup to a $15 billion valuation while prompting a debate over the future of patient care.
Miami-based OpenEvidence, founded by serial entrepreneur Daniel Nadler in 2022, said that many of America’s 1 million physicians processed more than 42 million prompts last month. Doctors are using the company’s chatbot to scour medical journals and clinical guidelines to help diagnose and treat patients.
The ads-powered platform has grown largely by word of mouth, penetrating a sector where few tools have seen similar traction. “We’re the first viral consumer internet app in healthcare,” Nadler told the FT in an interview.
OpenEvidence has won praise from medical professionals who have found it helped ease workloads, according to interviews with eight senior physicians.
But it faces a nascent threat from large AI companies such as OpenAI and Anthropic, who are making a push into the space. Its growing influence has also prompted scrutiny from researchers concerned over the accuracy of its results, as doctors grow more dependent on an AI tool shaping the course of treatments.
The company’s rapid ascent has attracted nearly $1 billion in investment in the past 18 months, from backers including Andreessen Horowitz, Blackstone, Thrive Capital, and Sequoia. The group raised $250 million in its latest funding round in September at a $15 billion valuation.
OpenEvidence booked $100 million in “ad buys”—a metric that covers current and future advertising commitments—for this year at the end of 2025, according to a person close to the company. The startup is on track to generate between $400 million and $500 million through ads by the end of 2026, the person added.
Nadler’s company has penetrated an established market for medical software that was sluggish to incorporate generative AI models. Dutch IT group Wolters Kluwer released an AI version of its leading subscription-based UpToDate medical software tool in October 2025, nearly two years after OpenEvidence entered the market.
Central to OpenEvidence’s pitch is a focused source list consisting of peer-reviewed journals such as the New England Journal of Medicine and the Journal of the American Medical Association.