9 evidence-graded facts. Click any card for the full summary and sources.
The landmark 2017 National Academies report — the most rigorous evidence review to date — found substantial evidence for only three indications: chronic pain in adults, chemotherapy-induced nausea (oral cannabinoids), and MS-related spasticity. Nearly everything else sits at "limited" or "insufficient."
Medical Evidence STRONG EVIDENCEDronabinol and nabilone (synthetic THC) are approved for chemo nausea and AIDS wasting; nabiximols (THC+CBD spray) is approved for MS spasticity in 25+ countries; Epidiolex (CBD) for severe epilepsy. The medical channel exists and works — it is simply narrower than the dispensary menu suggests.
Medical Evidence STRONG EVIDENCECannabinoids kill cancer cells in petri dishes and mice — as do thousands of compounds that never become medicines. No controlled human trial has shown cannabis treating cancer. It genuinely helps with chemo nausea and appetite; abandoning oncology treatment for cannabis has cost lives.
Medical Evidence MIXED / UNSETTLEDSome state-level studies found fewer opioid prescriptions and overdoses after legalization; later re-analyses with more states and years found the effect reversed or vanished. Individual patients report real substitution benefits; population evidence is unstable. An open, important question.
Medical Evidence MODERATE EVIDENCETHC does reduce intraocular pressure, but only for 3–4 hours, requiring constant intoxicating doses to protect the optic nerve. Ophthalmology societies explicitly do not recommend it. A real effect, a poor medicine — the classic case of mechanism ≠ treatment.
Medical Evidence MODERATE EVIDENCEA widely shared claim that gastric acid converts CBD to psychoactive THC comes from simulated lab fluid, not human bodies. Human studies measuring THC and metabolites after oral CBD find no meaningful conversion. Epidiolex trials at high doses confirm: patients do not get high.
Medical Evidence STRONG EVIDENCEDronabinol (Marinol) — synthetic THC — was approved four decades ago for chemotherapy-induced nausea and AIDS-related appetite loss, later joined by nabilone. Whatever the plant's legal status, cannabinoid medicine itself is old, established pharmacology.
Medical Evidence MODERATE EVIDENCENabiximols (Sativex), a 1:1 THC:CBD oromucosal spray, is approved across Europe, Canada and elsewhere for multiple-sclerosis spasticity that resists standard treatment. Trials show real but modest responder rates — it helps a subset of patients, not everyone.
Medical Evidence MIXED / UNSETTLEDRegistries show PTSD among the top qualifying conditions, yet the first randomized controlled trial (2021) found all cannabis arms beat placebo only marginally and inconsistently, and a large veteran cohort analysis linked cannabis use to worse outcomes over time. Hopeful mechanism, unproven treatment.
Medical Evidence