Evidence Health

How an answer gets made

Evidence Health finds the official evidence first and only then explains it. Below is one real question followed from start to finish, using the actual label text in our library.

  1. 1

    You ask

    In your own words. No medical terms needed.

    Who should not take metformin?
  2. 2

    We find the evidence

    The question is matched by meaning against every label passage. These two come back on top, from the same FDA label.

    1Contraindications
    Metformin hydrochloride tablets are contraindicated in patients with: Severe renal impairment (eGFR below 30 mL/min/1.73 m 2 ). Hypersensitivity to metformin. Acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.
    2Boxed Warning: lactic acidosis
    Risk factors for metformin-associated lactic acidosis include renal impairment, concomitant use of certain drugs (e.g. carbonic anhydrase inhibitors such as topiramate), age 65 years old or greater, having a radiological study with contrast, surgery and other procedures, hypoxic states (e.g., acute congestive heart failure), excessive alcohol intake, and hepatic impairment.
  3. 3

    The AI explains only those passages

    Plain language, with each point numbered back to its passage.

    The label says metformin should not be used by people with severe kidney problems (eGFR below 30), people who are allergic to metformin, or people with metabolic acidosis, including diabetic ketoacidosis.1

    It also carries a boxed warning about lactic acidosis, a rare but serious problem. The risk is higher with kidney or liver problems, age 65 or older, scans that use contrast dye, surgery, and heavy drinking.2

    Check with your doctor or pharmacist whether any of this applies to you.

  4. 4

    You can check it

    Every number leads to a real document you can open and read.

    Document
    U.S. FDA drug label, metformin hydrochloride tablets
    Manufacturer
    Northwind Health Company, LLC
    Label version
    4, published Jan 2026
    Retrieved
    Oct 2026

Ask your own question →

Before you ask: building the library

Answers are only as good as what they are built from, so the library is assembled ahead of time from official sources and refreshed on each source’s own schedule.

  1. Fetch from the source

    FDA drug labels, recalls and side-effect reports; medicine names from the National Library of Medicine; condition guides from MedlinePlus; study records from PubMed.

  2. Keep a traceable copy

    Every record keeps the source’s own version number and the date we retrieved it, so any sentence can be traced to one specific document.

  3. Split into passages

    Each label is cut into short passages along its own sections — Boxed Warning, Contraindications, Dosage — so a passage always knows where it came from.

  4. Index by meaning

    Each passage gets a meaning fingerprint, so “who shouldn’t take this?” finds the Contraindications section even though those words never appear.

What the AI is and isn’t allowed to do

The AI is the explainer, not the source. These rules are part of every request it receives.

  • Does: Answer only from passages it was handed

    The AI sees the retrieved passages and the question, nothing else. It is told to answer from those passages alone.

  • Does: Cite every point, then get checked

    Each statement carries a number pointing to its passage. Before you see the answer, every statement is checked against that passage; anything the passage doesn’t support is removed, and you’re told how many.

  • Does: Put emergencies first

    Fixed rules, not the AI, spot emergencies like an overdose or chest pain. You get your region’s emergency number straight away, with no research answer underneath.

  • Does: Say when the evidence isn’t there

    If nothing relevant is found, you get “I don’t have enough information”, not a confident guess.

  • Never: Never invent a source, study or number

    It cannot cite anything that was not retrieved, because it is never given anything else to cite.

  • Never: Never give personal medical advice

    No diagnosis, no dose for you, and never “start, stop or change” a medicine. Those decisions stay with your doctor or pharmacist.

Where you’ll see it

The same evidence library sits behind every part of the site.

Medicine pagesA plain-language leaflet built from the FDA label, with boxed warnings and recalls at the top and the exact labels listed at the bottom.LiveAsk a questionType a question in your own words and get a cited answer with the passages it used.LiveConditionsMedlinePlus explanations of 55 common conditions, linked to medicines whose labels mention them.LiveCompareTwo medicines side by side, section by section, from their labels.LiveMy medicinesSave the medicines you take and see a warning if one of them has been recalled.Live
Check two medicines togetherNeeds a licensed interaction database, which free official sources do not provide.Coming
Understand a reportPaste a letter or lab report; we pick out the medicines, conditions and results and link them to official information. Read on our own server only.Live

Information, not advice

Evidence Health explains what official sources say. It does not diagnose, prescribe, or decide whether a medicine is right for you. In an emergency, call your local emergency number. See the sources we use →