In the 1990s, research into THC (tetrahydrocannabinol) led to the discovery of the endocannabinoid system, which led to major advances in medical cannabis research. Although it is one of the physiologically active substances ``cannabinoids'', compared to THC, CBD has received almost no attention.

CBD became globally known in 2013. The trigger was epilepsy.

Epilepsy is a disease that causes repeated seizures. Epileptic seizures are caused by the excessive excitement of nerve cells in the cerebrum, which causes a strong electrical current to flow through them, and they are said to occur most often between children and those in their 20s, but the cause is still not clearly understood. Treatment involves taking drugs that suppress the abnormal excitability of nerve cells, but there are cases of ``intractable epilepsy'' that are difficult to cure with drugs.

In 2013, the documentary program ``WEED'' about Charlotte Figge, a girl living in Colorado, USA, who suffers from ``Drapée syndrome'', one of these ``intractable epilepsy'', was broadcast and attracted attention from all over the United States.

Produced by Dr. Sanjay Gupta, a physician who was once an opponent of medical marijuana, the program featured a story about how homemade CBD oil subsided epileptic seizures that would not go away no matter what he tried. Initially, many people stood up and accelerated the trend of legalizing medical marijuana in the United States.