Cannabis foods, more informally known as medibles, are food products made with cannabis in herbal or resin form as an ingredient. They are consumed as an alternate delivery means to experience the effects of cannabinoids without smoking or vaporizing cannabis or hashish. Instead, the cannabinoids are put into cake, cookie, brownie, or other foods, and are consumed for medicinal purposes.
Tetrahydrocannabinol (THC) is generally considered to be the primary active substance in cannabis. Along with other psychoactive cannabinoids, THC is a hydrophobic oil, meaning it is insoluble in water but soluble in lipids (oil/fat) and alcohol. Using either one of these to extract THC from cannabis is required to have the cooked product be psychoactive. During preparation the cannabis or its extract must be heated sufficiently or dehydrated to cause decarboxylation of its most abundant cannabinoid, tetrahydrocannabinolic acid (THCA), into psychoactive THC.
Some authors claim that oral consumption of cannabis, when properly cooked, is a more efficient way to absorb cannabinoids than smoking it. Oral consumption of cannabinoids can result in a similar psychoactive effect or "high" as smoking marijuana, although it may be delayed or mitigated due to slower absorption of the THC from the digestive tract. Whereas the effects from smoking cannabis are usually felt within a few minutes, it can take up to two hours to reach full effects after ingesting it. Marijuana produces THCA, an acid with the carboxylic group (COOH) attached. THCA is not very psychoactive. It is only when the carboxyl group is removed that THC becomes psychoactive. When marijuana is smoked, the THC behind the hot spot is vaporized as the hot air from the burn is drawn through the joint or pipe or blunt or chillum to the unburned material. The liquid THC and other cannabinoids have a boiling point of between 180-200 °C (355-392 °F). Before they turn gaseous, the carboxyl group is released from the molecule as carbon dioxide and water vapor at around 106 °C (220 °F). In the cooking of edible psychoactive products, some research indicates heating cannabis to a temperature of 122 °C (251 °F) for 27 minutes to be the optimum method to optimize THC:THCA ratios.
Because oral doses are processed by the liver before entering the bloodstream, oral THC produces high levels of active metabolite 11-OH-THC, while smoked cannabis does not. 11-OH-THC is more potent than THC and crosses the blood–brain barrier more easily.