Drugs affect our body chemistry and are used in a variety of different ways to help healing - painkillers, antibiotics, vaccines and so on. When new drugs are developed they need to be tested prior to medical use in humans, and seeing how this is done is one part of GCSE Biology. Clinical trials involve the large scale testing of drugs on volunteers and provide essential information about their safety and efficacy (how effectively they work). During clinical trials, the volunteers are monitored closely and any side effects can be discovered too.
Clinical trials need to be carried out under carefully controlled conditions in order not to come to the wrong conclusions and jeopardise patients' safety. In a blind trial, the best method of testing, the patients do not know whether they are being given the drug or a placebo. A placebo is something that looks like the drug but actually contains no active ingredients. In some trials, neither the doctors nor the patients know who has taken what until the trial is over. This is a very good way of filtering out any errors.
In the 1950s, a drug called thalidomide was being developed and testing was done on people with respiratory diseases. After some clinical trials it was also found to be an anti-emetic, in other words, it prevented vomiting. During pregnancy, many women suffering from morning sickness bought the drug. It had never been tested on pregnant women and shortly after it went on sale, some of these women gave birth to badly deformed babies, half of whom died. Following this tragedy, regulations about clinical trials before new drugs could be sold were changed, in order to avoid something like this occuring in the future. Thalidomide is still being used but as an anti-cancer and anti-leprosy drug, where its safety has been thoroughly ensured.