Short answer
Some cannabis compounds reduce nausea. The best evidence covers THC-based drugs for chemotherapy-induced nausea and vomiting (CINV). Two THC drugs carry FDA approval for that use. CBD has no FDA approval for nausea, and human trials of CBD alone for nausea are few. Cannabis also can cause nausea in long-term users through cannabinoid hyperemesis syndrome.
Cannabis for Anti-Nausea Effect: A Practical CBD and THC Guide
What the evidence shows
Trials in the 1970s and 1980s compared oral THC (dronabinol) with older antiemetics such as prochlorperazine. Several trials found fewer vomiting episodes in the THC group. A Cochrane review pooled those trials. Reviewers rated the evidence as low to moderate quality. Samples were small and reporting was weak. Newer drugs such as ondansetron and aprepitant came after these trials. THC is not a first-line antiemetic.
Route changes timing. Inhaled cannabis reaches the blood in minutes. Oral capsules and edibles peak at 60 to 180 minutes. Oral THC absorbs at changeable rates, so blood levels vary between patients.
CBD for a Queasy Feeling: What Research Says and How to Use It Safely
FDA-approved cannabinoid drugs
Two products are FDA approved for CINV in patients who fail other antiemetics:
- Dronabinol (Marinol), synthetic THC, capsule. Approved 1985. Label dose: 5 mg/m² before chemotherapy, then every 2 to 4 hours, up to 6 doses per day. Schedule III.
- Nabilone (Cesamet), synthetic THC analog, capsule. Approved 2006. Dose: 1 to 2 mg twice daily. Schedule II.
Labels list drowsiness, dizziness, dry mouth, memory problems, and euphoria as side effects. Both drugs can impair driving.
CBD for nausea
No CBD product has FDA approval for nausea. Epidiolex, the only FDA-approved CBD drug, treats Dravet syndrome and Lennox-Gastaut syndrome, two forms of epilepsy. Most support for CBD against nausea comes from animal studies. Human data is thin.
Hemp-derived CBD with less than 0.3% THC is legal at the federal level in the US. State rules differ. Labels do not always match content. A 2017 study in JAMA tested 84 CBD products sold online: 26% contained less CBD than the label stated and 43% contained more.
Risks and limits
- Cannabinoid hyperemesis syndrome: long-term, heavy cannabis use can cause repeated vomiting and abdominal pain. Hot showers and baths relieve symptoms for some users. Stopping cannabis ends the cycle.
- Drug interactions: CBD inhibits CYP2C19 and CYP3A4. It may raise blood levels of clobazam, warfarin, and some statins. THC adds to sedation from opioids, benzodiazepines, and alcohol.
- Impairment: THC slows reaction time and short-term memory for hours after use.
- Potency: flower and concentrate THC content ranges from under 1% to over 80%. Dose is hard to control.
What to ask a clinician
Bring the product label, the THC and CBD content per dose, and the route of use. Ask about interactions with your current drugs. Ask if a prescription cannabinoid fits your plan better than a store product. Check your state health department rules before you buy.