New drugs need to be tested and trialled before doctors prescribe them and patients take them. This allows drugs to be checked for:
This is important as some drugs are toxic, and have other side effects that might be harmful to people
This is also known as efficacy, and checks how well the drug cures the disease, or improves symptoms.
This varies, and has to be closely controlled, as too high a concentration might be toxic.
There are three main stages of testing: