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What You Should Know About Clinical Trials
Clinical trials help find new ways to improve health. Participating has risks and benefits you need to learn about before signing up.

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What You Should Know About Clinical Trials

Clinical trials are research studies in which ordinary people can help doctors and scientists find ways to improve health. Each trial tries to answer questions and find better ways to prevent, diagnose or treat diseases and conditions.

Most clinical trials are studies that compare new or existing drugs, products or therapies to others. Many will evaluate medications or treatments that have not been tested before. The trials try to find out whether one treatment works as well as or better than another. These studies must follow a pre-defined plan (protocol) that outlines:

  • Who may participate.
  • Schedules of tests, procedures, drugs and dosages.
  • Length of study.

Types of clinical trials
Different kinds of clinical trials include:

  • Treatment. New treatments or combinations of existing treatments are tested to see how safe and effective they are.
  • Prevention. These look for better ways to help prevent a disease in people who have never had it or to keep it from returning.
  • Screening. These seek the best ways to identify a disease or condition.
  • Quality of life. These look at ways to improve comfort and quality of life for people with chronic illnesses.

Federal regulations require any clinical trial in the U.S. to be approved and monitored by an Institutional Review Board (IRB). This board is composed of doctors, statisticians, participant advocates and others. The IRB makes sure the clinical trial:

  • Is ethical.
  • Protects the rights of study participants.
  • Does not involve more risks than potential benefits.

Risks and benefits
Taking part in a clinical trial involves both potential benefits and risks.


  • New drugs and procedures may have unknown side effects or risks.
  • Treatments may be less effective than current therapies or not work at all.
  • It may require more time than would a non-trial treatment. This includes trips to the study site, more treatments, hospital stays and complex drug dosages.
  • Participants wishing for a new treatment may get assigned a placebo or standard treatment instead.


  • Care from top doctors
  • Access to drugs and therapies not on the market yet
  • Successful treatment or reduction of symptoms in some cases
  • Satisfaction of helping others

How you're protected
Researchers must adhere to strict ethical and legal codes. Most clinical research is federally regulated with safeguards meant to protect participants.

Regulations require clinical trial teams to provide details of the study before you sign on. This is known as informed consent. You should be told about:

  • Treatments
  • Tests
  • Possible benefits and risks

Researchers often report results at meetings, in medical journals and to government agencies. No participant names are mentioned.

Signing up
If you think that a clinical trial is right for you, be sure to ask questions until you are sure you are fully informed. Find out if you will have to pay for your treatment or tests. Ask how the trial will affect your daily life. Know what is expected of you.

To ensure trial results are reliable, you need to follow instructions carefully. You can ask the study team questions at any point. You can also leave a study whenever you want - before it starts, during the study or in its follow-up period.

To find a trial, you may want to start with the website The National Institutes of Health maintains this site as a registry of trials in the U.S. and worldwide. It recently listed more than 137,000 trials in 182 countries.

Emily A. King contributed to this report.

By Howard Seidman, Contributing Writer
Created on 02/11/2002
Updated on 12/20/2012
  • Learn about clinical studies.
  • National Cancer Institute. What are clinical trials?
  • National Institute of Mental Health. A participant’s guide to mental health clinical research.
  • National Institutes of Health. NIH clinical research trials and you: The basics.
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