What's in marijuana? Well, at this point in time we can say that marijuana contains 483 compounds that have been identified, and at least 84 of those are cannabinoids. The cannabinoids are a class of chemicals that react with certain receptors within the brain. Of these various cannabinoids it is only delta-9-tetrahydrocannabinol, or THC, that is psychoactive. THC is usually the most abundant cannabinoid found within marijuana with cannabidiol (CBD) being the second most common. And now that I've said that, I should also say that what I just said is not true! Technically speaking, that is. What raw marijuana actually contains are the acid forms of these two cannabinoids (THCa and CBDa), and it is the heat applied to marijuana that converts these compounds into their non-acid forms. Again, let me reiterate that only THC is psychoactive. The other forms have many health benefits, but they are not mid-altering. Additionally, marijuana contains a variety of aromatic chemicals called terpenes. Below, though, is a list of several of the more common cannabinoids found in marijuana along with the medicinal properties they are believed to possess.
Now there's one more cannabinoid that needs to be mentioned. When you consume marijuana as an edible, the THC is broken down in the liver into 11-hydroxy-delta-9-THC. This version of THC is also psychoactive, but it's effect is somewhat different from that of the THC that takes a more direct route to the brain when inhaled. Additionally, whereas THC inhaled may produce an altered state in about 10 to 15 minutes which then lasts for a couple of hours, it may take marijuana that is ingested 45 minutes to an hour to make its way through the liver and onto the brain, and then the high state may last for up to four hours. Furthermore, THC in the blood has a half-life in the body of about 19 hours, while 11-hydroxy-delta-9-THC has a half-life of about 50 hours. If you are unfamiliar with edibles, it's very easy to ingest too much and have a very uncomfortable experience.
In addition to the cannabinoids contained within marijuana, the plant also contains a large number of terpenes. These are the essential oils found within cannabis and other plants that give a plant its particular aroma. Additionally, it's believed that these terpenes work synergistically with the cannabinoids to produce a variety of healing effects. Below is a chart that lists the healing properties believed to be associated with the five most common terpenes.
And finally, here are some great videos on the constituents of cannabis.