OpenEvidence raises $250 million, doubles valuation to $12 billion as healthcare AI heats up

OpenEvidence Secures $250 Million Funding Round

OpenEvidence, the healthcare AI startup widely known as "ChatGPT for doctors," has closed a $250 million funding round that doubles valuation to $12 billion, the company announced this week1

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. Thrive Capital and DST co-led the Series D investment, marking the fourth fundraise for the Cambridge, Massachusetts-based company in less than a year2

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. The AI startup has now raised nearly $700 million since its inception, with its valuation skyrocketing from $1 billion in February to $6 billion in October and now $12 billion3

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Founded in 2022 by Daniel Nadler, who previously sold Kensho Technologies to Standard & Poor's for approximately $700 million in 2018, OpenEvidence has attracted backing from Google Ventures, Nvidia, Kleiner Perkins, David Sacks' Craft Ventures, Sequoia Capital, Coatue, and Mayo Clinic1

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. The rapid valuation increase reflects growing investor confidence in healthcare AI, a sector that received an estimated $14 billion in seed-through-growth-stage funding in 2025, representing 63% growth compared to $8.6 billion raised in 20242

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How the AI Platform for Doctors Works

OpenEvidence provides an AI-powered research tool that helps physicians make clinical decisions at the point of care. Unlike consumer-facing chatbots trained on the open internet, the platform's AI models are trained on data from scientific journals and medical literature through strategic partnerships with publications like the New England Journal of Medicine5

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. The platform functions as a specialized medical search engine that delivers citation-linked answers, allowing physicians to verify AI-generated content and explore topics in depth3

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The system can search medical journals to help doctors formulate patient diagnoses, identify potential treatment options, and generate side-by-side comparisons3

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. When medical associations publish updated treatment guidelines, physicians can use OpenEvidence to quickly identify changes from previous editions. Under the hood, the platform employs AI models focused on different clinical sub-specialties, with a "conductor" AI analyzing each prompt and routing it to the model best suited to provide an answer3

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Massive Adoption Among U.S. Physicians

OpenEvidence claims to be the most widely used AI platform by doctors in the U.S., with more than 40% of physicians utilizing the tool across over 10,000 hospitals and medical centers1

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. In December alone, the platform supported approximately 18 million clinical consultations from verified physicians, up from about 3 million consultations per month a year earlier2

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. Last year, more than 100 million Americans were treated by a doctor using OpenEvidence2

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The platform is free for doctors and generates revenue through advertising, a model that has already proven successful2

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. CEO Daniel Nadler told CNBC that OpenEvidence topped $100 million in annual revenue last year, with 95% of new users hearing about the app from other doctors through organic growth1

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. Beyond clinical question-answering, the company launched a tool in August that doctors can use to create medical notes and enrich them with external healthcare data3

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. The platform also serves as a clinical education tool, enabling medical schools to generate exam questions while students use it as a study assistant3

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Competition From Tech Giants in Healthcare AI

The funding round comes as major AI companies are launching competing health offerings. OpenAI recently introduced ChatGPT Health, while Anthropic launched Claude Healthcare, both HIPAA-compliant versions of their chatbots4

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. OpenAI earlier this month introduced a feature that can answer consumers' medical questions and likely has the resources to create a more sophisticated version capable of fielding inquiries from clinicians3

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However, Nadler believes OpenEvidence's specialized approach and existing data advantage position it ahead of competitors. "We've already gathered hundreds of millions of real-world clinical consultations from verified physicians - that feedback loop is incredibly hard to replicate," he told CNBC5

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. He emphasized that even if competitors copied the playbook today, they would still be far behind because of the real-world usage data and partnerships with medical journals and associations5

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Why Healthcare AI Matters Now

Nadler pointed to the massive opportunity in healthcare, which accounts for nearly 20% of U.S. gross domestic product with $5 trillion in annual spending1

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. "Health care is the largest segment of the real economy," Nadler said. "People realize there could be a lot of winners in the space"1

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. The need for such tools is urgent: if a doctor tried to stay current by reading only the new evidence in the top 10 medical journals and only the most recent changes to their specialty guidelines, it would take nine hours of their day, each day2

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OpenEvidence will use the new capital for research and development initiatives and to procure computing infrastructure3

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. Nadler emphasized his company's focus on building relationships with physicians in small practices that lack IT departments or budgets for expensive software, noting that "most health care in America isn't happening at billion-dollar hospitals in New York or San Francisco"5

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. While AI giants have been on an acquisition spree, Nadler wants to keep OpenEvidence independent and is waiting for larger businesses like SpaceX, OpenAI and Anthropic to go public before considering an IPO5

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