Hi there and thanks for posting

There is more information titled what are clinical trials? including a section about the different types of clinical trials on the website. This explains trials and what they hope to achieve and explain how people are recruited onto different parts of trials.

Usually in treatment trials patients will either have the standard treatment already available on the NHS or the treatment on trial, although in some cases there are several treatments being compared at the same time.

There may be occasions where a placebo drug is involved in a trial. However this would be explained to the person being recruited onto the trial and written up in the trial information. Placebo drugs shouldn't cause side effects in theory however because the patient won't know whether it is the placebo or actual drug they are taking it can sometimes cause what is known as nocebo effects. This is negative thoughts or expectation that a drug will cause them some harm in some way.

I hope this helps.

All the best

Naomi