Updated on January 28, 2019. Medical content reviewed by Dr. Joseph Rosado, MD, M.B.A, Chief Medical Officer
While medical marijuana can treat constipation and diarrhea, it can also cause either one. For patients who smoke or vaporize medical weed, these side effects are often non-existent. If you use edibles or oils to treat your condition, however, you may experience these side effects of medical cannabis.
Possible Side Effects of Medical Cannabis
Like other medications your doctor may prescribe, medical marijuana can cause several different side effects. For physicians, their goal is to provide you with medicines that offer you the best benefits and the least side effects.
Unlike prescription drugs, some medical cannabis doctors may recommend medical weed because of its side effects. If you cope with insomnia, for instance, your doctor might suggest medical pot because it can cause drowsiness and doesn’t pose the long-term risks of prescription sleep aids like Ambien.
How Does Medical Weed Cause Diarrhea and Constipation?
The cause behind diarrhea and constipation due to medical weed, is an area that’s gone unstudied. Some early studies suggest tetrahydrocannabinol (THC), one of several cannabinoids, slows down the digestive tract.
Another possibility is that edibles, as well as oils, may contain additional ingredients that affect how fast or slow your digestive system processes food. Another cannabinoid, cannabidiol (CBD), is considered a potential motivator for diarrhea.
With time, researchers may discover why medical weed causes diarrhea and constipation in some instances. While the legal standing of medical marijuana is one reason this topic has gone unresearched, another is due to the rarity of this side effect.
Signs of Diarrhea and Constipation From Medical Cannabis
What are Symptoms of Diarrhea from Medical Cannabis?
- Loose stool
- Abdominal cramps or pain
- Urgency to have a bowel movement
What are the Signs of Constipation from Medical Weed?
- Hard or lumpy stool
- Having fewer than three bowel movements a week
- Straining to express stool
- Feelings of being blocked
- Inability to empty stool from your rectum
If you begin to experience diarrhea or constipation, it’s critical to visit your physician.
Long-Term Side Effects of Diarrhea and Constipation
When they occur for brief periods, diarrhea and constipation don’t result in long-term side effects. If they last for weeks, however, you may need to change your treatment plan. Or, the symptoms could indicate a more serious problem.
What are some Conditions that Cause Diarrhea and Constipation?
- Crohn’s disease
- Celiac disease
- Irritable Bowel Syndrome (IBS)
- Colon cancer
- Rectal cancer
- Anal fissure
Long-term side effects of not treating your constipation include anal fissures, impaction, and rectal prolapse. The most substantial risk of untreated diarrhea is dehydration. No matter which symptom you’re experiencing, notify your physician as soon as possible.
How to Avoid and Manage Diarrhea and Constipation From Medical Marijuana
Because the medical community doesn’t have a complete understanding of why medical marijuana can cause diarrhea and constipation, there is no tried-and-true recommendation for avoiding or managing either cannabis-induced symptom.
In most cases, your medical marijuana doctor may recommend adjusting:
- Your diet
- Your strain of medical weed
- How you administer cannabis
- Your dosage of medical pot
Keeping a symptom tracker as you and your physician change your treatment plan is often helpful, as well.
Talk to Your Medical Marijuana Doctor About Your Diarrhea and Constipation
Whether you or a loved one is using medical weed, it’s essential you work with your medical marijuana doctor to ensure your treatment is offering you the maximum benefits — in most cases, medical pot does. If you’re experiencing unwanted side effects, schedule an appointment to discuss them with your physician, as they may be able to recommend useful changes.
Learn why some cannabis users experience diarrhea as a side effect and how to combat side effects to get the most out of your cannabis.
Why Marijuana’s Effect On Your Poop Affects Your Brain
One of the hot topics in neuroscience these days is the influence of the gut’s microbiome on the brain. While the microbiome is comprised of all the microorganisms in the body, it’s the bacteria that’s gaining the most focus. So you might ask: does marijuana effect the microbiome? And if so, what affect does it have on brain function?
Gut Bacteria and the Brain
The bacteria in the gut can have a substantial impact on brain function by modulating the enteric nervous system, which is a layer of nerve cells that line the intestinal tract from the esophagus to the rectum. This enteric nervous system communicates directly with the brain. Research has revealed that this “Gut-Brain Axis” can impact everything from brain development to psychological health by affecting immune function in the brain, producing hormones and neurotransmitters, and directly activating bundles of neurons that travel up to the brain.
Consequently, fecal transplants are gaining in popularity , not just for intestinal problems, but for ones involving the brain including Parkinson’s disease and autism.
By impacting the Gut-Brain Axis, bacteria may influence cognitive functioning in many ways. For one, it could modulate the efficiency of the organelles that serve as the body’s power plants. You may recall from high school biology that they’re called mitochondria. Mitochondria convert the energy from food, in the form of glucose, into a useable from of energy, called ATP. So altering the gut microbiome could negatively impact cognitive function by reducing mitochondrial function.
Marijuana’s Effect on Poop and Brain Function
Frequent use of THC-rich marijuana is also associated with cognitive problems, but it’s unclear if these problems are related to changes in the gut microbiome. A recent study published in the ‘Journal of Neuroimmune Pharmacology’ investigated the relationship between marijuana use, microbiome composition (assessed from stool samples), mitochondria function, and cognitive performance.
The study found that marijuana users had substantially different microbiomes than non-users, and the microbiomes of marijuana users were associated with reduced mitochondria function. Reduced mitochondria function generally means that less energy is produced for use by cells throughout the brain and body. It’s like going to a gas station and only filling your tank up three-quarters of the way. You just can’t drive as far and so you’ll arrive at your destination slower.
Interestingly, the microbiomes of non-users were comprised largely of a type of bacteria that’s consistent with a plant-based diet, while the bacteria of marijuana users were associated with an animal-based diet. The higher the ratio between plant-diet-based bacteria to animal-diet-based bacteria was associated with better performance on tests of attention, inhibitory control, and cognitive function in marijuana users. Therefore, the further that the marijuana user’s gut microbiome deviated from that of non-users, the worse their mitochondrial function and cognitive performance became.
These findings highlight the importance of diet and gut bacteria on cognitive performance in marijuana users. Fortunately, there are ways of improving your gut microbiome, even if you use marijuana. These include eating lots of fruits and vegetables, or consuming probiotics which you can get in everything from yogurt to kombucha to probiotic armies stuffed into pills.
One caveat is that this study did not assess if or how marijuana changed the microbiome. Future studies are needed to assess the impact of marijuana on the microbiome in a “cause-and-effect” manner, as opposed to simply looking at the “association” as this study employed. Further, future research should focus on identifying whether rescuing the microbiome through probiotic or dietary intervention can improve some of the cognitive deficits associated with frequent marijuana use.
Lastly, it’s unknown if cannabidiol or cannabidiol-rich marijuana could counter the effects of THC-rich marijuana on the gut’s microbiome. Cannabidiol is known to block the actions of THC, as well as directly activate serotonin receptors, which are even more prevalent in the gut than the brain. Either way, the Gut-Brain Axis represents an exciting new way to modulate both the positive and negative effects of marijuana on health.
Bacteria in the gut has a huge effect on the brain – what does pot do to this bacteria? Learn more about marijuana's effect on poop and how that might affect the brain.