Hemp is an annual plant that contains more than 400 chemicals, more than 60 of which have similar chemical properties, so they are collectively referred to as cannabinoids. Common varieties: The cannabis plant commonly used for smoking refers to "hashish," which includes the leaves and flowers of the cannabis plant. The stamen of the cannabis plant produces a sap-rich and cannabinoid-rich resin, which is collected and dried and heated or pressed to form a variety of colors such as yellow-brown, brownish red to black, which can be smoked like a cannabis plant. Organic solvents such as petroleum ether and ethanol can extract cannabinoids from hemp plants or cannabis resin and obtain a viscous liquid of dark brown or dark green - hemp oil.