Cannabis in the human body works by activating the endocannabinoid system. Endocannabinoids are fat-based neurotransmitters that activate both CB1 and CB2 cannabinoid receptors throughout the body. Endocannabinoids are also naturally produced by the body.
Endocannabinoids can be agonists or excitatory, which means they can enhance the effect felt by neurotransmitters in the body. They can also be antagonistic or inhibitory and reduce the level of a certain neurotransmitter in the body. This is important to note because the psychoactive component of cannabis, Δ9-tetrahydrocannabinol (THC), can be both a CB1 and CB2 receptor agonist and antagonist, depending on the amount consumed. Cannabidiol (CBD) is an antagonist, meaning it acts opposite to THC.
Essentially, at high doses, THC activates CB1 receptors in the dorsal vagus nerve complex, the nerve responsible for controlling vomiting or vomiting. In addition, CB1 receptors in the gastrointestinal tract actually slow down motility or digestion and promote their opposite anti-nausea effect in the brain.
Treating Nausea with Medical Cannabis
According to the Australian Department of Health, relatively high THC cannabis is recommended for the treatment of nausea compared to using CBD-only products. It is important to note that, in rare cases, long-term cannabis use can cause cannabinoid hyperemesis syndrome, a syndrome that causes cyclical vomiting until use stops and may require ER treatment for secondary dehydration or other complications.
If smoking helps manage nausea, it is important to choose a hemp flower that is high in THC because this chemical compound directly affects the dorsal vagus nerve, which controls the nausea and vomiting responses in humans. Another ideal option is to use a vaporizer or vape pen if the patient is concerned about the dangers of smoke. Smoking or vaping may carry additional health risks.
Because oral cannabis starts working in an hour or two and lasts longer in the body, many patients choose to inhale cannabis for immediate relief and faster recovery. Taking medical marijuana orally can be tricky to get the exact dosage right, but it can deliver cannabinoids (chemical compounds found in marijuana) without the need for smoking or vaping.
- Shown to control nausea in cancer patients, a population that doesn’t always get severe nausea control with traditional antiemetics, or anti-nausea medications
- Slows intestinal motility
- Increases appetite
- Dysphoria or depression
- Paranoid delusions
- Dry mouth
- Potential for cyclic vomiting syndrome in high doses
Treating Chemotherapy-Related Nausea and Vomiting with Cannabis
High doses of cannabis THC are recommended for the treatment of chemotherapy-induced cancer-related nausea. Studies show that cannabinoids, including prescription ones, are more effective than traditional anti-nausea drugs in reducing vomiting and nausea in patients undergoing cancer chemotherapy. If you are being treated with emetogenic chemotherapy, a type of chemotherapy that causes more vomiting and nausea, cannabis is no more effective than anti-nausea medications for relieving symptoms.
A 2016 review discusses studies on cannabis and nausea, noting that activation of the endocannabinoid system can increase levels of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) when the patient experiences motion sickness or after certain types of anesthesia. Unfortunately, this evidence has been demonstrated in animal studies, but human clinical studies are yet to be done.
In addition, there is promising evidence that cannabis can help the 25-59% of chemotherapy patients who develop premature nausea. Anticipatory nausea occurs when a patient’s acute nausea after chemotherapy is not properly treated, and then the patient has a conditioned nausea response when returning to the clinic for repeat treatment sessions. Researchers believe that, unlike traditional antiemetics, cannabis may help this group of patients.
It is important to consider that some highly concentrated THC and CBD oil extracts have been touted as potential cancer treatments, but these products have not been evaluated in clinical trials. It’s best to stay away from foods that say they can cure cancer.
Treating HIV-Related Nausea with Cannabis
Many human immunodeficiency virus (HIV) patients take medication to suppress the effects of the virus on their body, but then suffer side effects from those medications. These antiviral drugs, called protease inhibitors, are very effective in keeping patients from getting sick, but they cause nausea and vomiting similar to chemotherapy-induced nausea.
In patients with HIV, research supports the use of medical marijuana and dronabinol to treat nausea and cachexia, or wasting syndrome, which causes severe weight loss. When patients were given large doses of cannabis or dronabinol, their weight increased by 3.5-3.9% percent; this is something traditional anti-nausea medications do not improve.
More research is needed in this area, as many of these studies are short and contain small numbers of participants or some research bias when it comes to dronabinol.
Cannabis-Derived Prescription Medications for Nausea
The following are marijuana-derived or synthetic cannabinoid medications that treat nausea. The first two are approved by the U.S. Food and Drug Administration (FDA).
Dronabinol (Brand name Marinol)
- For effective treatment of chemotherapy-induced nausea and vomiting, cancer-associated nausea and vomiting, and HIV-associated nausea and vomiting
- Contains synthetic THC
- Taken orally by capsule
- Analysis of studies show low to moderate quality of information
- Shown to be as effective as traditional antiemetics, or anti-nausea medications in treating chemotherapy-induced nausea
Nabilone (Brand name Cesamet)
- For cancer-associated nausea and vomiting, HIV/AIDs related nausea and vomiting, and chemotherapy-induced nausea and vomiting
- Synthetic THC
- Taken orally by capsule
- Studies have been determined to be very low to moderate in quality
- Shown to be more effective than traditional antiemetics, or anti-nausea medications
- Treats chemotherapy-induced nausea and vomiting as well as increases appetite in cancer patient
- A mixture of ethanol extracts of THC and CBD in a 1:1 ratio (2
- A liquid spray that absorbs oromuscosally, or through the cheeks in the mouth
- Insufficient evidence for controlling nausea and vomiting, but shown to be as effective in the reviewed and completed study (11)
- For treatment of chemotherapy-induced nausea and vomiting
- Injection into muscles
- Low to moderate quality of evidence from studies analyzed
- Insufficient evidence for controlling nausea and vomiting
Before using medical marijuana, it is recommended to talk to your doctor about the presence of nausea. In general, everyone reacts differently to medications. Your healthcare provider can help you determine your dosage to control your nausea, as well as any concerns you may have about marijuana’s psychoactive properties.
We do not intend to give this as professional medical advice. Let the specialist independently diagnose or prescribe treatment based on the information provided on this page. Always consult your doctor before making any decision about taking any medical condition in the first place.