There is a chance you will get side effects you (and your doctor) were not expecting. If you are in a phase 1 trial, the researchers may not be able to tell you much about side effects. You will be told everything they do know before you agree to take part in the trial. You will be asked to report all your side effects to the study staff. You may be asked to keep a diary at home or fill in questionnaires about feeling sick or tired. You can withdraw from a trial at any point.