Artificial intelligence startup OpenEvidence banked a $210 million series B round as it looks to expand its strategic content partnerships to build out its advanced medical knowledge library.
OpenEvidence developed an AI-powered medical search engine and generative AI chatbot exclusively for doctors that summarizes and simplifies evidence-based medical information.
Google Ventures and Kleiner Perkins co-led the series B round. Sequoia Capital, which led OpenEvidence’s $75 million series A round earlier in 2025, also backed the round. The round also included investments from Coatue, Conviction and Thrive.
OpenEvidence has raised more than $300 million since its founding and this latest funding vaults its valuation to $3.5 billion, the company said.
Founded in 2022 by Daniel Nadler, Ph.D., the company touts that it's the most widely used medical search engine among U.S. clinicians, claiming more than 40% of physicians in the U.S. use its platform.
Nadler previously founded Kensho Technologies, which was sold for $700 million to S&P Global in 2018.
OpenEvidence is growing rapidly. It is actively used across more than 10,000 hospitals and medical centers nationwide, and it continues to grow by more than 65,000 new verified U.S. clinician registrations each month, the company claims.
OpenEvidence asserts its platform has seen a 2,000%-plus year-over-year growth rate. In July 2024, OpenEvidence supported approximately 358,000 physician consultations in one month. One year later, the company now handles that many each workday and supports more than 8,500,000 clinical consultations by physicians per month, executives said.
The company offers its chatbot to physicians for free, and the product has grown organically through word of mouth between doctors, Nadler said.
OpenEvidence has formed strategic content partnerships with the American Medical Association, The New England Journal of Medicine, The Journal of the American Medical Association and all 11 JAMA specialty journals including JAMA Oncology and JAMA Neurology.
The company has strategically differentiated itself from other medical AI chatbots by being an early mover and collecting tens of millions of clinical consultations as well as through its content partnerships with medical journals that represent the gold standards of medical knowledge, Nadler noted.
As AI copilots become more commoditized, Nadler sees the evolution of these technologies as somewhat similar to TV streaming services where the focus in on the content—a consumer can sign up for Disney Plus to watch "Moana" or sign up for Paramount Plus to watch "Star Trek."
"Streaming as a concept, or the technology involved in streaming has now been pretty commoditized. These copilots are eventually going to get there, but then you differentiate around content and partnerships," Nadler told Fierce Healthcare in an interview. "That's a big part of the difference of OpenEvidence. If you're a doctor, and you want to ask a question on OpenEvidence, that same question on ChatGPT, for example, is going to pull a generic answer, maybe from the abstract that it scraped from the public Internet. It's not going to pull the exact answer on who is the control group and what will be the breakdown of the efficacy of the drug by different cohorts in the study and how does it differentially affect pregnant women versus non-pregnant women."
OpenEvidence uses trusted source of the highest-quality scientific evidence to inform its answers, giving physicians, medical researchers and healthcare professionals faster access to clinically relevant evidence, according to the company. The platform rapidly surfaces relevant medical knowledge, synthesizes medical research and gives clinicians the power to make faster, more evidence-based decisions.
Clinicians using OpenEvidence, which is HIPAA-compliant, can input clinical questions or patient case details and receive point-of-care answers grounded in the latest research, complete with references and even follow-up suggestions.
OpenEvidence’s core search product is designed for speed—returning evidence-based answers in about 5–10 seconds.
Along with the fresh funding, the company also released an AI agent purpose-built for physicians for more advanced medical research. Called DeepConsult, the AI agent is a "digital twin of a Ph.D.-level researcher," according to Nadler.
DeepConsult was designed to help physicians ramp up on a new body of knowledge and can provide a comprehensive Ph.D.-level research report, delivered to their inbox, within a matter of hours.
OpenEvidence DeepConsult agents use advanced reasoning models to autonomously analyze and cross-reference hundreds of peer-reviewed medical studies in parallel—surfacing not just direct answers but also connections across the literature that might otherwise go unnoticed. The result is an evidence-based synthesis that would typically take a human researcher months of painstaking effort to produce for a single clinical topic.
OpenEvidence is offering DeepConsult free to all verified U.S. clinicians regardless of their institution or workplace, the company said.
Clinicians are overwhelmed by information overload, with the volume of medical research published annually doubling every five years.
“At a time when U.S. healthcare faces the dual challenges of clinician burnout and a projected physician shortfall of nearly 100,000 by 2030, the question of AI's role in bridging the gap is paramount," Nadler said.
Google Ventures is banking on OpenEvidence's continued growth, and it was the first major investor in Nadler's first AI company.
"Daniel Nadler is a magnet for talent, attracting top AI researchers and a world-class medical advisory board," said Sangeen Zeb, general partner at Google Ventures. "As a firm with a life sciences team largely composed of physicians and scientists, we deeply understand the challenges clinicians face with traditional tools. Physicians are drowning in information but starving for timely insights. OpenEvidence changes that equation, bringing clinicians into the modern era. As early investors in Daniel’s first company, Kensho, GV has been privileged to know him for over a decade. He is a once-in-a-generation founder building one of the fastest-growing technology applications ever seen."