The word cannabis covers many products. Evidence for a purified prescription CBD solution cannot be transferred to a dispensary gummy. Results from a THC:CBD oral spray do not prove that smoked flower, a balm, or a different ratio will produce the same benefit.
How to read the evidence levels
- Approved medicine: The FDA has reviewed a specific cannabinoid drug for a defined indication. Approval does not extend to retail cannabis products.
- Modest or product-specific evidence: Multiple studies suggest a small average benefit, often with common adverse effects and important limits.
- Early or uncertain: Studies are small, inconsistent, observational, or do not establish whether cannabis caused the result.
- No established benefit: Reliable clinical evidence does not support the treatment claim, or research has not shown a meaningful effect.
Approved cannabinoid medicines
Rare seizure disorders
The FDA has approved purified cannabidiol, sold as Epidiolex, for seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex. It is a prescription drug with dosing, interaction, and liver-monitoring requirements. Store CBD oil is not an equivalent substitute.
Chemotherapy nausea and HIV/AIDS appetite loss
The FDA has approved synthetic THC-related medicines for chemotherapy-associated nausea and vomiting and for appetite loss associated with AIDS. These approvals apply to the named drugs and indications, not to all cannabis products. See our cancer patient guide for supportive care distinctions.
Conditions with modest or product-specific evidence
Chronic pain
The 2025 AHRQ living review found small short-term pain improvements for certain comparable THC:CBD products, alongside more dizziness, sedation, and nausea. Evidence was insufficient for many product types and long-term outcomes. Review the full chronic pain evidence summary.
Multiple sclerosis symptoms
NCCIH reports that cannabis-based products may provide modest benefit for some multiple sclerosis symptoms, especially patient-reported spasticity and pain. Effects depend on product and outcome, and adverse events are common enough to matter in the decision.
Early, mixed, or uncertain evidence
Insomnia and sleep disturbance
Trials use different cannabinoids, doses, and patient groups. The first CBN insomnia trial missed its primary outcome, while a high dose improved some secondary measures. Our sleep gummies evidence guide separates sleep onset, maintenance, architecture, and next-day function.
PTSD and anxiety
Observational reports and small studies do not establish a general treatment effect. THC can worsen anxiety or paranoia in some people, and heavy use can complicate mental-health symptoms. Evidence for prescription-level CBD doses should not be applied to low-dose retail products.
Inflammatory bowel disease
Some studies report symptom or quality-of-life changes, but that is not the same as healing intestinal inflammation. Cannabis should not replace disease-modifying treatment. Read the Crohn's disease guide for endpoints and safety questions.
Migraine, neuropathy, arthritis, and fibromyalgia
Research is heterogeneous and often small. A state may allow these diagnoses even when comparative clinical evidence remains limited. Use a defined treatment goal, review adverse effects, and avoid assuming that one route or ratio represents all cannabis.
Claims without an established treatment benefit
Cannabis has not been shown to cure cancer, reverse dementia, treat autism's core features, or replace proven treatment for serious infection, epilepsy, inflammatory disease, or psychiatric illness. Symptom relief and disease modification are separate claims. A product that helps appetite or nausea does not thereby treat a tumor.
Risks that change the decision
Important risks include impairment, falls, motor-vehicle crashes, anxiety, psychosis vulnerability, cannabis use disorder, cannabinoid hyperemesis, cardiovascular effects, pregnancy and breastfeeding exposure, and drug interactions. Older adults may be more sensitive to dizziness, sedation, and medication burden. See the older-adult safety guide and CBD interaction guide.
Questions for a clinical visit
- What symptom are we measuring, and over what time?
- Which product, cannabinoid ratio, route, and dose match the evidence?
- Could it interact with my medicines or health conditions?
- What adverse effect means I should reduce the dose or stop?
- How will impairment affect driving, work, caregiving, or fall risk?
- When should we decide whether it helped enough to continue?
Legal access is a separate step. Use the licensed dispensary locator to reach official state registries and the delivery guide to verify fulfillment rules.
Primary and government sources
Review standard: Evidence levels describe the cited literature, not an individual recommendation. State eligibility rules and clinical evidence answer different questions.