Introduction
The era of "hallucinating" chatbots is ending. For clinicians and researchers, a new standard has emerged: AI medical search engines. Unlike general-purpose chatbots (like the standard ChatGPT), these tools are built on a "retrieval-first" architecture. They don't just generate text; they find real documents, read them, and synthesise an answer based only on what they found, providing clickable citations for every claim.
This guide compares the four heavyweights of this new class—Perplexity, Elicit, Consensus, and Semantic Scholar—plus the essential citation-checker scite. We also explore how to integrate these research tools into a safe clinical workflow using iatroX.
Why “AI search” is different from “AI chat”
It is critical to distinguish between a Generative tool and a Retrieval tool.
- AI Chat (Generative): Predicts the next word based on training data. It is fluent but prone to making up facts ("hallucinations") because it relies on internal memory.
- AI Search (Retrieval + Citations): Searches a live database (the web or a paper repository), retrieves relevant text, and then summarises it. It is grounded in external evidence. If it can't find a source, it shouldn't answer.
Reliability signals
When evaluating these tools, look for:
- Inline Citations: Can you click a little number [1] and go directly to the PDF?
- Corpus Boundaries: Does it search the whole web (noisy) or just a database of 200 million academic papers (clean)?
- Transparency: Does it tell you if the paper is a pre-print or peer-reviewed?
Head-to-head by job-to-be-done
Job 1: “Find papers fast”
Winner: Semantic Scholar / Elicit
- Semantic Scholar: This is the best "discovery" engine. It uses AI to understand the meaning of your search, not just keywords. Its "TLDR" (Too Long; Didn't Read) feature gives you a one-sentence AI summary of a paper's abstract, allowing you to scan 50 papers in the time it used to take to scan 5.
- Elicit: Elicit goes deeper. It is an "AI Research Assistant." You can upload a PDF or search a topic, and it will extract data into a structured table (e.g., "What was the sample size? What were the side effects?"). It is perfect for building a literature review or a rapid evidence synthesis.
Job 2: “Answer a clinical research question with citations”
Winner: Consensus / Perplexity
- Consensus: This is an AI search engine built exclusively on top of peer-reviewed literature. When you ask a question (e.g., "Does magnesium help with leg cramps?"), it runs a search, extracts the findings, and synthesises a "Consensus Meter" showing if the literature generally says "Yes," "No," or "Possibly." It is the safest tool for pure academic queries because it ignores non-academic web noise.
- Perplexity: The best "all-rounder." Perplexity searches the live web but focuses on high-quality domains. It provides a natural-language answer with rigorous footnoting. It is excellent for broader context, epidemiology, or finding guidelines that might not be in a journal database (e.g., NHS policy documents).
Job 3: “Check how a paper is cited”
Winner: scite
- scite: Traditional citation counts are meaningless (a paper might be cited 100 times because 100 people said it was wrong). scite uses "Smart Citations" to tell you how a paper was cited: Supporting, Contrasting, or Mentioning. Before you base a clinical decision on a study, check it in scite to ensure it hasn't been widely refuted.
A safe clinician workflow
Don't rely on one tool. Use a "Swiss Cheese" safety model:
- The Orientation (Perplexity): Ask a broad question to get the landscape. "What are the recent developments in the management of HFpEF?"
- The Deep Dive (Consensus / Elicit): verify the specific claims. "Show me meta-analyses on SGLT2 inhibitors in HFpEF."
- The Safety Check (scite): Check the key trial. "Has the EMPEROR-Preserved trial been contradicted?"
- The Synthesis (iatroX): Bring it back to the ward. Use iatroX to summarise the UK-specific guideline context (NICE/BNF) for this treatment and log the learning for your CPD. iatroX acts as your "clinical workspace" where the research meets the regulations.
Prompt patterns that reduce hallucination risk
Even with search tools, you must prompt carefully.
- The "Grounding" Prompt: "Answer this question using ONLY the provided search results. If you cannot find the answer in the papers, state that you do not know."
- The "Sceptic" Prompt: "Summarise the evidence for X, but specifically highlight any conflicting data or limitations in the study designs."
FAQ
Is Perplexity better than Google Scholar? For answers, yes. Perplexity synthesises the information. Google Scholar just lists links. Use Scholar when you know exactly what paper you want; use Perplexity when you have a question.
Is Elicit free? Elicit operates on a credit system. You get a generous free tier, but heavy use (especially data extraction from many PDFs) requires a subscription.
Can I use these tools for patient decisions? These are research tools, not clinical decision support systems. They summarise literature, which may be outdated or not applicable to your specific patient. Always verify against a live clinical guideline (like CKS or the BNF) before prescribing.