Cannabis plants contain a variety of phenolic compounds. Cannabidiol (CBM), cannabidiol (CBD), tetrahydrocannabinol (THC), tetrahydrocannabidiol (THCV), and cannabidiol (CBDA) have been isolated), tetrahydrocannabinol (THCA), tetrahydrocannabidiol (THCUA), cannabidiol (CBN), amyl resorcinol (CBG), Cannabinerol (CBNB) and more than 40 kinds, including tetrahydrocannabinol It has a strong stimulating effect on the nervous system and is the main hallucinogenic addictive toxic substance. Cannabidiol compounds are very unstable and are particularly sensitive to high temperature and ultraviolet light. During the storage and drying process of cannabis, THC can be gradually converted into THC. Cannabidiol can also be converted into THC under certain conditions. And cannabidiol generally does not produce hallucinogenic effects on people.

The content of toxic ingredients in cannabis varies with the place of origin and variety. Cannabis generally distributed in India, West Asia, North Africa, and Central and South America has a high content of tetrahydrocannabinic acid and is mostly toxic. The THC content of industrial (fiber or oil) varieties is generally less than 0.3%, and usually less than 0.1% under ordinary cultivation conditions. The THC content of medicinal varieties is generally more than 0.3%, and the THC content of cannabis used to produce drugs is generally more than 3%. The tetrahydrocannabinic acid content of cannabis varies greatly in different growth periods. About 20 days after emergence, the seeds mainly contain cannabichrome acid (CBCA), and then the content of tetrahydrocannabinic acid gradually increases, reaching a peak at 100-150 days. In the same plant, tetrahydrocannabinic acid has the highest content in young leaves and immature ears, and little in old leaves.

my country has carried out research on the screening of low-toxic cannabis resources and the breeding of new varieties. A batch of low-toxic resources with THC content below 0.3% has been selected and a new low-toxic cannabis variety Yunma 1 has been cultivated. Japan (1972) and EU countries have screened a batch of low-toxic cannabis varieties (THC content <0.3%).