There are many drugs which come from plants for example heroin, morphine and codeine are all processed from Opium Poppy. Cocaine is derived from Coca Leaves, and Aspirin comes from Willow Bark. Drugs have to be tested to make sure they are safe to ensure it doesn’t harm the human, and they have to make sure they actually work (cure the disease, etc.) The drugs are tested on human cells artificially grown in the lab. The drugs are tested with computer models, if the drugs pass this stage then they proceed to be tested on animals they tend to put a known amount of the substance on the animal and monitor any noticeable side effects. If they then pass this stage the drugs approach the Clinical Trials, this is when healthy people volunteer for the drugs to be tested on them. If it works on them then the drug will be tested on people with the illness to see if it cures it.