Until recently, the most well-known compound in cannabis was delta-9 tetrahydrocannabinol (THC). This is the most active ingredient in marijuana.

Marijuana contains both THC and CBD, but the compounds have different effects.

THC is well-known for the mind-altering "high" it produces when broken down by heat and introduced into the body, such as when smoking the plant or cooking it into foods.

Unlike THC, CBD is not psychoactive. This means that it does not change the state of mind of the person who uses it. However, it does appear to produce significant changes in the body and has been found to have medical benefits.

Most of the CBD used medicinally is found in the least processed form of the cannabis plant, known as hemp.

Hemp and marijuana come from the same plant, cannabis sativa, but they are very different.

Over the years, marijuana farmers have selectively bred their plants to be very high in THC and other compounds that interested them, either for a smell or an effect they had on the plant's flowers.

On the other hand, hemp farmers have not tended to modify the plant. It is these hemp plants that are used to create CBD oil.