2. Mescaline
Mescaline ranks second on our list of easiest illegal drugs to make at home by using legal ingredients. It is a psychedelic hallucinogen drug belonging to the same class of drugs as LSD, PCP or DMT. Mescaline is a substance that is constituent of some cacti, one of them being San Pedro species. Since it is one of the main ingredients for making mescaline, you might have difficulties in finding it or spend years on growing some. But, you will have no problems if you live in a place such is Arizona, for example, where you will have an abundance of San Pedros in your surroundings, which would put mescaline among the easiest drugs to make at home by using legal ingredients. So, what ingredients do you need to make mescaline? Well, only a cactus, and then just cook it, according to some recipes we have found. But, to make things more serious, you will need to do some more chemistry, as suggested on Erowid.