CBD is sourced from the hemp plant. CBD is extracted from non-marijuana strains of the cannabis plant. The marijuana plant and the hemp plant are both from the 'cannabis' family, but hemp does not contain sufficient amounts of ingredient known as THC. THC is the ingredient in cannabis that has 'psychoactive' effects and it is particularly prevalent in the marijuana cannabis plant. 

Hemp cannabis does not contain enough THC to cause 'psychoactive' effects and is therefore industrially produced specifically to allow us to benefit from CBD without the effects of THC.