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NIH MedlinePlus the Magazine, Trusted Health Information from the National Institutes of Health

Clinical Trials: Key to Medical Progress

A Photo of a Lab Worker

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Clinical trials are research studies that test how well new medical approaches work in people. Each study answers scientific questions and tries to find better ways to prevent, screen for, diagnose, or treat a disease. Clinical trials may also compare a new treatment to a treatment that is already available.

There are two basic kinds of trials: observational and interventional. An observational study is done to find out what causes a human health condition or disease. A famous example is the Framingham Heart Study. Since 1948, researchers have followed four generations of family members in Framingham, Massachusetts, to see what affects their hearts. Some of the key findings, which we now take for granted, are that high blood pressure, high-fat diets, and smoking are not good for the heart. An interventional study tries to find ways to treat or prevent a specific condition or disease. For example, researchers may test different drugs to control high blood pressure. There are clinical trials going on all the time in nearly every area of medical research.

To Find Out More

To find out more about clinical trials and how to participate, go to:

Clinical Trials Information for Patients and Caregivers

(A Web site devoted to information about children and clinical trials, sponsored by the National Heart, Lung, and Blood Institute)

People who take part in clinical trials hope to benefit in some way. They may welcome the chance to play a more active role in their own health care. They may gain access to new treatments before they are widely available, or help others by contributing to medical research.

The latest, most complete information about clinical trials is available at the Web site. This is a free, confidential online resource from the National Institutes of Health (NIH). Anyone with a computer and Web browser can use the site to find complete listings of clinical studies in the United States and abroad.


After you enter the Web site, you can search for a trial by the name of the disease, the location of the study, the type of treatment, or the sponsoring institution. The results show you what studies are under way and whether a trial is seeking volunteers. They also tell you the purpose of the study, where and when it will take place, and whom to contact for more information.

" is a powerful tool for the health care consumer, and it has untold benefits for the public health, too."

— National Library of Medicine Director Donald A. B. Lindberg, M.D.

"From the very beginning, has been designed for use by patients," says Donald Lindberg, M.D., director of the National Library of Medicine (NLM), which manages the Web site. "With patients taking an increasingly active role in their own health care, they now have a chance to learn more about clinical studies on everything from Alzheimer's disease to zinc supplements. Without question, it has helped medical investigators with their research recruiting efforts, too."

Launched in February 2000, currently contains information on more than 27,000 trials. The site is very popular with the public. Over 20,000 people visit the site each day, and there are about 8 million page views monthly. The site is updated daily with new information. has many helpful consumer features. If you are interested in breast cancer trials, for example,
the site also links you to NLM's MedlinePlus (, where you will find in-depth information, including recent news articles and an interactive tutorial on the topic. It also links to NLM's Genetics Home Reference site ( to help you understand genetic factors that can increase the incidence of breast cancer. Also, it lets you search medical journal references via NLM's PubMed (, and it links to the National Cancer Institute (, the lead NIH institute on this particular topic.

"It's really one-stop shopping," says Dr. Lindberg. "It lets people dig deeper for information on their disease or condition. is a powerful tool for the health care consumer, and it has untold benefits for the public health, too."

How to Participate

A variety of federal agencies sponsor clinical trials, including the NIH, the Department of Defense (DOD), and the Department of Veterans Affairs (VA). In addition, medical institutions and pharmaceutical companies also conduct trials.

 No More Hand-Me-Downs: Research Designed for Children

Children andClinical StudiesChildren are not "little adults" when it comes to treating their health problems. They need medicines, devices, and treatments designed especially for their developing brains and bodies. And clinical research is the best way to find out which therapies work best for children.

Have you ever questioned why research is done in children? A new NIH Web site discusses why research in children is important, what happens during a study, safety measures, and other important information. Join experts, parents, and children themselves as they talk about their experiences with clinical research at

Summer 2008 Issue: Volume 3 Number 3 Pages 4 - 5