Clinical research (recherche clinique) is medical research to test new treatments and therapies using human tests subjects. 

Clinical Trial (essai clinique) or Interventional study (étude interventionnelle) is a research study to evaluate the effects of a medicine, behavior or intervention. It usually includes a control group or a placebo.

A control group (groupe témoin) is the group that does not receive treatment to measure how the other tested subjects do.

A placebo (un placebo) is a pill or liquid similar to the treatment under test but does not do anything.

A healthy volunteer (un volontaire sain) is a person who participates in the trial and has no know health problems.

A patient volunteer (patient volontaire) has a condition and wants participates to potentially diagnose, treat, or cure it.

Randomization (randomisation) is when two or more alternative treatments are given to test subjects by chance to increase reliability.

Clinical trials are usually conducted in four phases. (les 4 phases)

Single- or double-blind studies or single- or double-masked studies (étude en aveugle ou double aveugle) are studies in which the volunters do not know which medicine is being given to them, to avoid bias.

Types of Clinical Trials

Diagnostic trials (essais diagnostiques) help establish better tests or procedures for diagnosing a specific condition or disease.

Prevention trials (essais préventifs) investigate ways to prevent a disease in people who have never had the disease or to prevent the disease from returning.

Quality of life trials (or supportive care trials) (essais cliniques pour améliorer la qualité de vie) aim at improving the quality of life and comfort of patients with a chronic illness.

Screening trials (essais de dépistage) try to determine the best way to detect certain illnesses or diseases.

Treatment trials (essais de traitement) test new treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.