Medical cannabis in brief
Medical cannabis is cannabis that a licensed clinician recommends for a specific health condition. It differs from adult-use cannabis because a state health program controls who can buy it, where it is sold, and how much a patient may possess. Under federal law, cannabis remains a Schedule I substance, so each state writes its own rules: its own qualifying condition list, its own possession limit, and its own patient registry.
Do not confuse medical cannabis with hemp-derived CBD. The 2018 Farm Bill removed hemp and hemp products that contain no more than 0.3 percent THC from the Controlled Substances Act. That is why hemp CBD can ship across state lines and medical cannabis cannot.
Who qualifies
Qualifying conditions vary by state. Common entries include:
- Chronic or severe pain
- Cancer-related nausea and wasting
- Epilepsy and seizure disorders
- Multiple sclerosis with spasticity
- Post-traumatic stress disorder
- Crohn's disease and inflammatory bowel conditions
- Glaucoma and terminal illness
Some states accept any condition a clinician finds debilitating. Others publish a fixed list and reject everything else.
How to get a medical cannabis card
- Read your state health department page for patient rules.
- Collect medical records that document your diagnosis.
- Book an evaluation with a clinician registered in your state.
- Submit the state application and pay the registration fee.
- Wait for approval and print or save your card.
- Buy from a licensed dispensary and keep the receipt.
- Renew before the card expires, since most states require a yearly review.
Product forms
- Flower: inhaled or vaporized, effects begin within minutes and last about two hours.
- Concentrates and vape oil: higher THC per dose, fast onset, easy to overdo.
- Tinctures: placed under the tongue, onset in 15 to 45 minutes.
- Capsules: measured dose, onset in 30 to 90 minutes.
- Edibles: onset in 30 to 120 minutes, longer duration.
- Topicals: applied to skin, no meaningful intoxicating effect.
Dosing basics
Start with the smallest amount that produces a result, then wait before taking more. A common starting point is 1 to 2.5 mg of THC. Keep a written log of product name, batch number, dose, time, and effect. CBD can blunt some THC side effects, so many patients choose a product with both cannabinoids rather than THC alone.
Safety and drug interactions
Reported side effects include drowsiness, dizziness, dry mouth, short-term memory trouble, and a faster heartbeat. THC is processed by the same liver enzymes as several prescription drugs, so it can change blood levels of warfarin, clobazam, and some antidepressants. Do not drive after use. Tell your pharmacist about every cannabis product you take, including CBD.
Travel and federal law
A state card is valid inside that state only. Do not carry cannabis across state lines, do not bring it to an airport, and do not take it to a job site that tests for drugs. A few states accept out-of-state cards, but most do not.