While hemp and marijuana are both varieties of the cannabis plant, there are two key differentiators. In terms of their chemical makeup, marijuana often has high concentrations of THC, which is the compound that gives users the euphoric or the feelings of feeling high. Hemp, however has low concentrations of THC and high concentrations of CBD. In fact, industrial hemp must have lower than 0.3% THC in order to be considered legal in the United States. Both plans have an incredibly long history of human use, rich with medicinal benefits as well as many practical uses.