Cannabis by itself has long been used for medical purposes and in recent decades has gained significant traction in becoming a common and preferred treatment for specific ailments. Cannabis is one of the fastest growing industries in North America. 

Clinical testing on humans can only begin after a pre-clinical phase, involving laboratory studies (in vitro) and tests on animals, which has shown that the experimental drug is considered safe and effective. However, no animal is sufficiently similar to humans (even genetically modified ones) to make human testing unnecessary. For this reason, the experimental drug must also be tested on humans.