Corpus Hahnemannicumproven and unproven in medicine

An independent reference on evidence-based medicine and the history of medical doctrines. Not a medical organisation, sells no products and does not replace a doctor's advice; in a life-threatening emergency call your local emergency number (in Russia 103 or 112).

Glossary

Medical glossary

Articles about medical research are full of words that are rarely explained: randomisation, blinding, conflict of interest. Here these concepts are put into plain language, alongside terms from the history of medicine, so that the past and the present can be read in the same language.

Knowing a term means seeing where the key question is hidden in a news story. Sometimes the single word "observational" changes the meaning of the whole headline.

— Editor's note

How studies are designed

Control group
Participants who do not receive the method being tested but get a placebo or usual care instead. The result is compared against them.
Randomisation
Assigning participants to groups by chance, so that the groups are alike and the result does not depend on the researchers' choices.
Blinding
A technique in which participants, and often researchers too, do not know who is in which group. This reduces the influence of expectations on the assessment.
Placebo
An inactive imitation of an intervention that looks identical to the real thing. It is used to separate the effect of the method from expectations.
Placebo effect
An improvement in how someone feels that comes from expecting a benefit rather than from the action of a substance.

How to read results

Systematic review
A piece of work that gathers and appraises all suitable studies on one question according to rules set in advance.
Levels of evidence
A rough hierarchy showing how reliable the conclusions of different types of study are.
Reproducibility
The ability of another group of researchers to obtain a similar result by repeating the work.
Evidence-based medicine
An approach in which decisions take into account the best research, the doctor's expertise and the patient's values. The term came into use in the early 1990s.

History of medicine

Humoral theory
An ancient doctrine that explained illness as an imbalance of the body's fluids.
Bloodletting
An old procedure that humoral theory regarded as a way to restore balance. It has been abandoned as a universal remedy.
Homeopathy
A doctrine created by Samuel Hahnemann at the turn of the 18th and 19th centuries. According to official assessments, there is no reliable evidence that it works.
"Organon of the Healing Art"
Hahnemann's main work, setting out the foundations of homeopathy. First published in 1810.

News and advertising

Conflict of interest
A situation in which the author of a study or publication stands to gain from a particular result. It is normally disclosed.
Pseudoscience
A doctrine that presents itself as scientific but does not follow scientific methods of testing. This is how the Russian Academy of Sciences Commission assessed homeopathy in 2017.
Natural course of an illness
The way an illness develops and resolves without intervention. It is often mistaken for the effect of a remedy.

Where these terms appear in the reference

  • Research

    How to read research: control groups, placebo, systematic reviews and levels of evidence.

  • Methods

    Evidence-based medicine, historical doctrines and alternative practices: what is known about them and how they are assessed.

  • Prevention

    How to spot an ad for a "miracle cure" and avoid losing time, money and health: a step-by-step check of the promises.

  • Questions

    Questions that help you discuss the benefits, risks and reliability of a particular method with your doctor.

  • Research

    How to read research: control groups, placebo, systematic reviews and levels of evidence.

  • Methods

    Evidence-based medicine, historical doctrines and alternative practices: what is known about them and how they are assessed.

  • Sources

    Which official assessments this reference relies on, what it deliberately does not do and where its limits are.

Sources

  • Cochrane Library
  • Russian Academy of Sciences Commission against Pseudoscience — memorandum on homeopathy (2017)
  • WHO — information for patients

This page reflects the state of knowledge on the date it was prepared. Scientific assessments and official guidance are revised as new research appears, so make decisions about your health together with your doctor.