How do I know if I am not receiving the experimental treatment in a clinical trial? 

Generally, there are two types of clinical trials: Uncontrolled and controlled. In an uncontrolled clinical trial, all participants receive the same experimental treatment.

In a controlled clinical trial, participants are separated into two groups so that doctors can compare how well different treatments work. The first is called the treatment group, or experimental group, which may receive one or more kinds of treatment. The other is called the control group, which receives the standard treatment -- the usual treatment for a particular disease. If no standard treatment exists, the group will receive a placebo, which is designed to look like a treatment but does not have any medicine in it. Participants are typically told before joining a clinical trial whether or not a placebo will be used.

Controlled clinical trials are often blinded. In a single-blinded study, the patient doesn't know whether or not she's receiving the experimental treatment or the standard treatment/placebo until the trial is over, but the doctor or nurse knows. In a double-blinded study, the patient and doctor both do not know whether the experimental treatment is being used until the trial is over. Blinding helps prevent individual biases and preconceptions from affecting the study's results. In either case, those that receive the experimental vs. standard treatment or placebo are chosen at random.

Your doctor can find out which group you are in if there's an important medical reason, including the potential for a severe adverse event -- or an unwanted negative reaction to a drug. But doing so may result in your removal from the trial.

types of research
What are the different types of clinical research?
Explaining Randomization in Clinical Trials
What happens during and at the end of a clinical trial?
During a clinical trial, the patient's treatment team -- including doctors, nurses, social workers and other health providers -- will provide care in a hospital or clinical setting...
I understand that not everyone is chosen to participate in a clinical trial. How do I determine if I am eligible?
All clinical trials have specific guidelines about who can participate. After you agree to join a trial, you will be screened by clinical staff to ensure you are eligible...
Why do people participate in clinical trials?
People participate in clinical trials for many reasons. Participants generally fall into two categories: Healthy volunteers and Patient volunteers.