The invention is a process for the controlled decarboxylation of cannabis wherein Medicinal Delta-9 tetrahydrocannabinol (Δ9-THC) and other cannabinoid medicinal substances are decarboxylated through a chemical reaction facilitated by a cofactor. The amount of medicinal cannabis decarboxylated will be directly proportional to the amount of cofactor used. Use a small amount of the cofactor and only some of the medicinal cannabis contained in raw cannabis will be converted from an acidic form into a non-acidic form. Use a large amount of the cofactor and most or all of the medicinal cannabis will be decarboxylated. The reaction is proportional to the molar mass of cofactor.