Who can participate in a clinical trial

Clinical trials have rules to determine who can participate in the trial. These are called eligibility criteria and are listed in the trial protocol. Learn about these eligibility criteria, and why you may not be able to participate. Find out whether your child can take part in a clinical trial.

Taking part in a clinical trial

Who can be part of a clinical trial depends on the design of the research project. Some trials can involve people of all ages, from children to the elderly, and with all types and stages of a disease or condition. In other trials, only people with specific characteristics can take part. Taking part in a trial is completely voluntary. Participants can withdraw at any time with no negative effects on the quality of their medical treatment or on their relationship with their doctor.

Some trials need healthy participants to test the safety of new interventions or tests, particularly in early-stage trials. These trials compare healthy participants with participants who are receiving medical treatment. Both groups receive the same test, procedure or drug. This means that researchers can compare the effects and side effects of the new test, procedure or drug between the 2 groups.

Many trials need participants who have the disease or condition that the new intervention targets. These participants test the new intervention to see what effect it has on their disease or condition.

How to be part of a clinical trial

If you are thinking of taking part in a clinical trial, the first step is finding out more about trials in general and what a particular clinical trial may involve. It is a good idea to seek out information from a number of sources.

Use our search function to find trials that may be suitable for you, and browse the listings of clinical trials websites and links for more information. Each listing includes contact details so you can find out more about a particular trial, including the criteria for participation.

Who to talk to

This website provides information about clinical trials in Australia. The Australian Government does not refer people to individual clinical trials.

You can talk to a range of people about clinical trials, including:

  • any health professionals involved in your care – general practitioners (GPs), specialists, nursing or allied health professionals
  • support groups or consumer health organisations with a focus on a particular disease or condition that interests you
  • other patients who have been involved in clinical trials.

Why you might not be able to take part

All clinical trials have rules about who can take part. These rules ensure that researchers conduct the trial safely and produce useful and reliable results.

We call these rules eligibility criteria. The eligibility criteria consist of:

  • Inclusion criteria, which must be met to allow someone to take part in a specific clinical trial.
  • Exclusion criteria, which do not permit someone to take part in that trial.

If you don’t meet the inclusion criteria, you will not be able to participate in the trial. Both inclusion and exclusion criteria may be based on:

  • age
  • gender
  • the type and stage of a disease or condition
  • previous treatment history
  • other medical conditions.

For example:

  • some trials seek people with certain diseases and conditions, while others need healthy people
  • the disease or condition may need to be at a particular stage
  • participants may not be allowed to receive another treatment at the same time
  • some trials need people of a certain age
  • there may already be enough people in a particular category who have joined the trial.

Medical tests

Before you can join a trial, you may need to have tests (such as a blood test) to see if you can take part. These tests may also allow the researchers to know more about your health before you start the trial. During the trial, you are likely to have more tests to see whether the treatment is working. At the end of the trial, a test may be able to tell if there has been an improvement.

Clinical trials and children

It’s important to have clinical trials that involve children because they differ from adults in both development and physiology.

Learn more on the World Health Organization’s website.

While research that includes children and young people is essential, there are particular ethical concerns. As a result, clinical trials involving children need to meet rigorous ethical standards.


Before enrolling your child in a clinical trial, you and your child should understand what the trial involves and the risks and benefits of participating. Because your child is a minor, the law may require you to provide consent for them to participate. If your state or territory does not have specific legislation about providing consent to medical treatment for a minor, the Family Law Act 1975 has provisions that may apply.

You should consider your child’s health and safety before agreeing to enrol them in any trial.

When you give your consent for your child to take part in a clinical trial, researchers may also ask your child for their permission or agreement. They must do this in an age-appropriate manner. This agreement is sometimes called the child's ‘assent’. Both you and your child should have the chance to ask any questions you want to ask before you agree to participate, and also at any time during a trial.

In order for a child to provide their consent or assent they must:

  • understand the research process
  • understand the purpose of the trial
  • be told what they are expected to do or what will happen to them during the trial.

Children should be able to express their views and any worries they might have about participating in a trial, and have their questions answered.

Children should always be given information in a form that they can understand.

A child’s individual level of maturity determines whether they are able to give their consent and what level of assent or agreement they can provide. For example:

  • infants are unable to take part in discussion about the research and its effects
  • young children cannot provide valid consent even though they may be able to
    • understand some relevant information
    • take part in limited discussion about the research
  • young people may still need additional consent from a parent or guardian even if they are mature enough to understand the research.

It is not possible to use a fixed age to decide what level of agreement or consent is appropriate because:

  • maturity varies from child to child
  • research projects are different.

More information on consent of minors is available on the Australian Commission on Safety and Quality in Health Care website.

Children under 16 years

A parent or guardian must give legal consent for children under 16 years of age to participate in a clinical trial. Children under 16 do not have the legal authority to make the decision themselves. However, you should involve your child in the decision so they know what will happen, can have a say, and be listened to.

Children aged 16 years and over

Young people over 16 can give legal consent to certain types of medical treatment. However, they usually cannot provide legal consent to participate in research until they are 18.

Some human research ethics committees do allow mature young people under 18 to give their consent for some kinds of research.

Getting information

Before giving consent for your child to take part in a trial, make sure you:

Researchers cannot enter your child in a trial if you do not consent. There should never be any pressure placed on you to give consent for your child to take part in a clinical trial.

If you are considering enrolling your child in a trial, a scientist or healthcare professional on the research team will talk with you. You may also wish to discuss your child’s participation in the trial with:

  • other family members
  • your child’s doctor
  • another healthcare professional.
Date last updated:
  • About clinical trials