A drug or procedure that is not yet Federal Drug Administration (FDA) approved for marketing.

A term, which means a treatment (drug, device, procedure) that is unproven or not yet scientifically confirmed with respect to safety and effectiveness

Part of a detailed inquiry; part of a systematic examination often applied to new drugs or therapies undergoing evaluation for human treatments.

Being studied; experimental.

Describes a drug or procedure allowed by the FDA (Food and Drug Administration) for use in clinical trials. Insurance companies tend to deny coverage to procedures, which are described as investigational.

In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the US Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered investigational in other diseases or conditions. Also called experimental.

under study; often used to describe drugs used in clinical trials that are not yet available to the general public.