OpenEvidence Hits $15 Billion Valuation as Doctors Flock to AI Search Tool

Nearly two-thirds of US physicians are using an AI-powered search engine to help make patient decisions, pushing little-known startup OpenEvidence to a $15 billion valuation and sparking debate about the future of patient care.

Miami-based OpenEvidence, founded in 2022 by serial entrepreneur Daniel Nadler, said America's roughly 1 million doctors processed more than 42 million prompts last month, using its chatbot to search medical journals and clinical guidelines for diagnosis and treatment help.

The ad-powered platform has grown mostly by word of mouth. "We're the first viral consumer internet app in healthcare," Nadler told the FT. Eight senior physicians interviewed said the tool helped ease their workloads, though researchers have raised concerns about the accuracy of its results as doctors grow more dependent on it.

OpenEvidence has drawn nearly $1 billion in investment over the past 18 months from backers including Andreessen Horowitz, Blackstone, Thrive Capital and Sequoia, raising $250 million in September at its $15 billion valuation. A person close to the company said it booked $100 million in ad buys for this year at the end of 2025 and is on track to generate $400 million to $500 million through ads by the end of 2026.

The startup faces a nascent threat from large AI companies such as OpenAI and Anthropic pushing into the space. It entered a medical software market slow to adopt generative AI; Dutch IT group Wolters Kluwer released an AI version of its UpToDate tool in October 2025, nearly two years after OpenEvidence launched.

Source: Ars Technica