Within the leaves, stems, and flowers of Cannabis plants live phytocannabinoids. There are more than a hundred of them, and they all contribute to the wonderful effects of the plant. These are the medicinal ingredients that treat the ailments in humans and animals. CBD is one of the most popular phytocannabinoids. Phytocannabinoids are cannabinoids that do not naturally occur in the human body like endocannabinoids, instead only being produced by plants.