The anti-nausea (antiemetic) properties of cannabis are one of the most largely studied and recognized medicinal applications of the plant, with a very clear body of evidence present in the medical literature supporting its use in people with cancer. The research shows that by manipulating the endocannabinoid system, we can regulate vomiting and nausea in both animals and humans, whether it is brought on by hormones, toxins, or motion.
The endocannabinoid system (ECS) is a molecular system of physiology that connects all areas of the body and manages their health status. If the ECS becomes overwhelmed from the stresses placed upon it, it can begin to fall into a state of disorder, leading to other areas of the body falling to the same fate. One of the main goals of the ECS is to maintain a state of balance and order (homeostasis), and when it cannot do that on its own, supplying it with supplementary cannabinoids can assist. You can learn more about the ECS in our article, The ECS Explained.
 Cannabis has a long history of use across many cultures for millenia, including for nausea and vomiting, and scientific research began in the mid-1970s to provide a solution for the side effects of cancer chemotherapy treatment in patients. The very first studies completed were using high-THC cannabis to successfully treat symptoms, which resulted in the development of a synthetic THC pharmaceutical product called Marinol, which is still prescribed today for appetite stimulation and nausea related to AIDS and cancer. Although, evidence does show that the drug, Marinol, and other synthetic versions of cannabinoids are not as effective as plant-based products (made directly from the cannabis plant) for many diseases. In particular, when it comes to nausea and vomiting, inhaled products are shown to provide a much higher success rate because they bypass the gastrointestinal system and the effects are immediate. In saying that, oral cannabinoid dosing can also provide relief for long term chronic issues. For more information, read our article on chronic pain.
The ECS works with both the endocannabinoids it creates, and the cannabinoids made by plants. Cannabis contains a full spectrum of cannabinoids that facilitate and support the optimal functioning of the ECS. When products made from cannabis varieties, such as hemp, contain a multiple of plant-based compounds, such as cannabinoids, terpenes, fatty acids, and phytosterols, they can induce a powerful healing effect, called the Entourage Effect. This term refers to the potent synergy that is created when we consume all of the naturally occurring plant compounds from cannabis in one dose, as opposed to isolated, such as in the case of a CBD oil. Our real goal then, is to consume compounds from the cannabis plant in their most natural form; full spectrum.
By 2002, scientists started turning towards cannabinoids without psychoactive side effects, such as cannabidiol (CBD), for its potent antiemetic properties.  Unlike tetrahydrocannabinol (THC), CBD has a low affinity for the CB1 and CB2 receptors, but it does seem to work indirectly on the 5-HT receptor, in the serotonin family of neurotransmitters. 
The information contained in this article is for informational purposes only and does not constitute medical advice of any kind. Prior to making changes to your lifestyle or treatment plan, always consult with a licenced medical practitioner. It is recommended those wishing to utilize cannabis, do so under the guidance of a physician who has experience in prescribing CBD and medical marijuana so that the dosage and delivery method may be customized to the patient. At the same time, well educated and aware persons may be their own highly informed health consultants. Availability of cannabinoid and cannabis products will vary based on country of origin and legal status.
Cannabis products can be smoked or vaporized to provide more immediate relief from nausea and vomiting, which is a preferred delivery system as it doesn’t require ingestion (and potentially not being able to keep the food down long enough to take effect), with the effects lasting one to three hours.
As is with the case of nausea, very often just the thought of having to ingest anything, including medicines, can cause symptoms to worsen. Commonly used strains include Mandala, OCD, White Knight, and Oregon Pinot Noir. Ingestible products, if consumed, take thirty to sixty minutes prior to taking effect and last six to eight hours. Vaporizers that use the whole plant, or CO2 concentrates in combinations of CBD and THC are also effective delivery methods.
When chronic nausea is the main issue, CBD products with a ratio of 20:1 or higher are typically advised and provided as capsules, edibles or sublingual drops. Always start with a micro dose to test for sensitivity, before titrating up to the next, until symptoms subside. The micro to standard dose is generally recommended to assist with symptoms. For chemotherapy induced nausea, a higher amount may be needed (see more in our article on cancer treatment). The majority of cannabis strains and varieties provide potent antiemetic effects, where you can find some treatment plans starting with 5 mg of THC and scaling up to 15 mg before chemotherapy begins.
Typically, indica strains have higher levels of CBD and less THC, with it being sought after for it's potent relaxing effects. Whereas sativa usually has higher levels of THC, which is the main compound studied, originally, and found valuable for the management of nausea and vomiting in chemotherapy patients. Although both indica and sativa have antiemetic properties and can enhance appetite. For more on appetite stimulation, see this article.
Due to the fact that research has revealed THC may be more effective at alleviating nausea than CBD (although new research is changing this stance), full spectrum CBD products may be the best course of action for a queasy stomach.
CBD helps with the healthy functioning of the vestibular system, with research clearly showing cannabinoids can help with chemotherapy induced nausea and vomiting, which may mean CBD can assist with motion sickness, and seasickness.
The cannabis health index is a scoring system based on the best available evidence present in the medical literature to date. For its antiemetic properties, cannabis rates as likely-probably efficacy.
According to the American and British medical association, cannabis is considered to be one of the best therapeutic compounds for nausea and vomiting. There are over forty studies conducted on the therapeutic use of cannabinoids to treat these symptoms, with one study pooling over one thousand chemotherapy cancer patients, discovering that synthetic THC given as an oral dose, provided relief to between 76-88 percent of users, with smoked cannabis providing relief in 70-100 percent. 
The currently commonly prescribed drugs for chemo-related nausea are 5-HT antagonists, which work by suppressing vomiting, but they do not, unfortunately, minimize nausea, and are not affected for delayed nausea and vomiting. Cannabinoids are very effective for these kinds of symptoms according to a 2011 study. 
In a 2017 study, researchers concluded that, “oral cannabinoids (i.e., tablets, capsules) are eﬃcacious for the management of nausea and vomiting associated with chemotherapy treatment, but capsules are associated with an increased incidence of adverse eﬀects compared with conventional antiemetic therapy. However, patients have shown a preference for oral cannabinoid therapy compared with some conventional antiemetics.” 
In a 2016 study, researchers discovered that the cannabinoids CBD and CBDA are highly effective antiemetics, including for acute nausea and anticipatory nausea, and did not produce any sedation or psychoactive effects. Stating that “the endocannabinoid system clearly plays an important role in the regulation of nausea” and that clinical trials “are warranted to improve the quality of life of patients undergoing cancer treatments by reducing the side effects of nausea and anticipatory nausea when it develops.” 
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