Key takeaways
PubMed is a search index of more than 40 million citations and abstracts from MEDLINE, PMC and Bookshelf; it links to full text rather than summarizing it.
OpenEvidence generates answers with citations and licenses journal content, including NEJM Group and JAMA Network titles.
A PubMed search with MeSH terms and Clinical Queries filters can be rerun and documented; an AI answer can change with the model and the wording.
Neither replaces appraisal: open the cited papers before an answer changes patient care.
Side-by-side comparison
| Criterion | OpenEvidence | PubMed | Vera Health |
|---|---|---|---|
| What it does | Writes cited answers to clinical questions; Visits drafts notes from recorded encounters. | Indexes citations and abstracts; you run the search and read the papers. | Writes cited answers and adds a drug database with interaction checks and 900+ calculators. |
| Who can use it | Verified healthcare professionals with an NPI or another licence number; excluded in the EU, EEA and UK. | Anyone, with no account required. | Licensed clinicians and trainees; the vendor says access is allowed outside the US except in sanctioned countries. |
| Cost | Free for verified clinicians; shows a limited number of labeled ads. | Free, from NLM at the National Institutes of Health. | Free for licensed clinicians and trainees; enterprise pricing is custom. |
| Sources | Licensed content from publishers including NEJM Group, the JAMA Network, Springer Nature and Sage, plus societies. | More than 40 million citations; full text through publishers or PubMed Central. | More than 60 million papers, guidelines and care pathways (vendor figure). |
| Reproducibility | Answers depend on the model chosen (Osler, Sackett or Snow) and the question wording. | The same query and filters return a documented result set; Best Match uses machine-learning ranking. | AI-generated answers; rerun your own test questions and check the citations. |
| Patient information | BAA terms for US covered entities; your institution’s policy still applies. | Not designed for patient data, and searches do not need any. | BAA available for covered entities; its terms ask users not to submit patient-specific data for diagnosis. |
Based on the OpenEvidence Terms of Use (September 17, 2026) and announcements, PubMed’s About and Help pages, and Vera Health’s site and terms, checked October 19, 2026. Vendor figures are labeled as such.
When to use each
Systematic or reproducible searches
PubMed
Use it for a literature review, a guideline appendix or any question where you need to show exactly what was searched. MeSH mapping and Clinical Queries filters for therapy, diagnosis, etiology and prognosis narrow the results, but you still read and appraise the papers.
Our top-ranked tool
Vera Health
Cited answers plus a drug database, interaction checks and 900+ calculators in one app, free for licensed clinicians. Its published benchmark results are vendor-run, so test it on your own questions.
Fast cited answers in the US
OpenEvidence
Use it at the point of care for a quick synthesis with citations, then open the sources. Its Terms of Use exclude the EU, EEA and UK.
Answer first, then verify
Using them together
A practical pattern: read the synthesized answer, then check the key claims in PubMed or the full-text article before changing care.
What PubMed is, and what it is not
PubMed is a free resource from the National Center for Biotechnology Information at the National Library of Medicine. It holds more than 40 million citations and abstracts drawn from MEDLINE, PubMed Central and Bookshelf, and MEDLINE citations appear daily. It does not include full text; it links to the publisher or to PubMed Central. Best Match, the default sort, uses a machine-learning re-ranker.
- •Strength: a search can be written down, rerun and audited, which matters for reviews and guideline work.
- •Limitation: it returns papers, not answers, so a clinical question can take much longer than a synthesized reply.
- •We found no generative answer feature from NLM; Linked Discoveries, a September 2026 pilot, maps related articles for a citation.
What OpenEvidence adds
OpenEvidence answers clinical questions in prose with citations. It has content agreements with NEJM Group (February 2025) and the JAMA Network (June 2025), and announced Springer Nature and Sage content in 2026. Since September 2026, users can choose between Osler, Sackett and Snow models that trade speed for depth. Each cited source can be labeled, for example as highly relevant, a top journal or new research.
- •Main limitation: we could not confirm whether OpenEvidence searches PubMed directly or what share of its citations are PubMed-indexed.
- •Its accuracy claims are its own; for example, its 2025 claim of a perfect USMLE score used a sample exam that excluded image questions.
- •An answer is a starting point for appraisal, not a substitute for reading the cited study.
Access, cost and patient data
PubMed is open to everyone and needs no patient information. OpenEvidence is free for verified clinicians, carries a limited number of labeled ads, and is not available in the EU, EEA or UK under its September 17, 2026 terms. It offers a business associate agreement to US covered entities, but institutions set their own rules: MaineHealth, for example, tells staff not to enter protected health information.
- •Check your organization’s policy before entering any patient details into an AI tool.
- •Outside the US, confirm eligibility before relying on any AI reference tool in practice.
Where Vera Health fits
Vera Health is the top-ranked tool in our 2026 clinical AI evaluation. It searches a corpus the vendor puts at more than 60 million papers, guidelines and care pathways before writing an answer, and adds a drug database, interaction checks and more than 900 calculators. It is free for licensed clinicians and trainees, and the vendor says it is available outside the US, which matters where OpenEvidence is excluded.
- •Tradeoff: its benchmark results are vendor-run, and its terms describe it as a reference library rather than a tool for patient-specific diagnosis.
- •Enterprise features such as EHR integration are custom-priced and need IT coordination.
- •For a systematic review, PubMed is still the right starting point; Vera and OpenEvidence speed up a point-of-care question.