What are nausea and vomiting?
Nausea and vomiting are not diseases themselves, instead, they are symptoms of other health problems. Nausea is the unshakable sensation of feeling sick or feeling the need to vomit. It is not necessarily painful but can be incredibly uncomfortable and make everyday tasks difficult. Vomiting, or emesis, is the physical act of being sick. The content of your stomach is voluntarily or involuntarily brought up through your oesophagus and out of your mouth. Nausea and vomiting can present themselves at the same time or one after the other. It is often thought that nausea is the precursor to vomiting. In other words, it is a way for your body to signal to you that you will be sick. However, this is not always the case. One can also be experienced without the other.
What can cause nausea?
The cause depends on the time scale and severity of the vomiting. If it only lasts for a few hours or less than two days it is normal. It could be a reaction to bad food, stress, motion sickness or something similar. These feelings should pass once the trigger is no longer around. If vomiting persists after 2 days (in adults) it could be the indication of something else. Cancer, concussion, meningitis, gallbladder disease, infections, appendicitis and more can all have vomiting as a symptom. At this point, it would be advised to speak with your doctor. Excessive vomiting has some negative side effects. If you are not able to keep eat or drink without being sick you can become severely dehydrated.
What can cause nausea?
Nausea is slightly more complex than emesis. Vomiting usually has a clear cause, and once the trigger has gone it surpasses. Nausea, however, can be brought on by environmental, physical or emotional triggers. Some causes of nausea are:
- Ear problems, infections etc.
- Head Injury or concussion
- Bacterial or viral infection
- Gastrointestinal problems
- Poison and toxins
- Heart attack
- Emotional Problems
Chemotherapy Induced Nausea and Vomiting
Nausea is particularly hard to treat because it is a common reaction to treatments for various different illnesses. Chemotherapy, the treatment for cancer, is well known for bringing on intense nausea. This is known as chemotherapy-induced nausea and vomiting, or CINV. It can be so bad that many patients undergoing chemo will experience what is known as anticipatory CINV. This is when feelings of nausea start before treatment has even begun.
During chemotherapy, nausea is caused by the release of serotonin in the gastrointestinal tract. Anti-emetics work by stopping serotonin from binding to the 5-HT receptors which stimulate feelings of nausea. For many, conventional anti-emetics are simply not strong enough to provide relief for their nausea. Not only this but once anticipatory nausea develops it is no longer responsive to pharmaceutical anti-emetics. Therefore, alternative options are needed. The vomiting that is brought on by chemotherapy and other medications is controlled well by conventional anti-emetics.
Would cannabinoids work?
One of the first documented uses of cannabis for nausea was in the 1970s for CINV. Since then, research into why cannabinoids can provide relief has progressed. It seems that the endocannabinoid system plays a big role in the regulation of feelings of nausea.
Cannabinoid receptors 1 and 2 have been found all over the gastrointestinal tract and in sites related to the uptake of serotonin. It is understood that cannabinoids such as CBD and THC could inhibit the interaction between serotonin and its receptors. One review of current evidence found that the introduction of cannabinoids was, in fact, effective in regulating feelings of nausea. However, the evidence that our endogenous cannabinoids have a part in this was inconsistent. Treating nausea and vomiting with cannabinoids is still seen to be quite controversial. This may be due to doctors not having enough, or the right information.
CBD can be used to support homeostasis and maintain a healthy immune system. It is not a cure, or medicine, but can provide relief from many physical and emotional issues. Medical research is limited due to its cost, but what has been discovered so far is very promising. Furthermore, the anecdotal evidence of the effectiveness of cannabinoids like CBD is overwhelming. If you are thinking about trying it out it is always best to do as much research as possible, and seek the advice of your doctor.
Singh, P., Yoon, S. and Kuo, B. (2016). Nausea: a review of pathophysiology and therapeutics. [online] NCBI. Available at:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4960260/ [Accessed 11 Jan. 2020].
Parker, L., Rock, E. and Limebeer, C. (2011). Regulation of nausea and vomiting by cannabinoids [online] NCBI. Available at:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165951/ [Accessed 11 Jan. 2020].