Mar 07th 2025

Can You Be Allergic to Cannabis?

For so many people, including those we serve in our clinic with medical cannabis certifications, using cannabis to treat the symptoms of certain illnesses provides much-needed relief that they couldn’t find with traditional pharmaceuticals. However, for some people, cannabis medicine isn’t an option because it produces adverse effects that negate the purpose of cannabis treatments.

Can you be allergic to cannabis? Why can some people use cannabis with no problems, but for others, using the plant can provide feelings of total misery. Here we’ll break down the reasons why some people may be allergic to cannabis, as well as talk about the condition called Cannabis Hyperemesis Syndrome, or CHS.

What an Allergy to Cannabis Looks Like

Some people have allergies, whether they be seasonal environmental allergies, like to pollen; or food-related, like to peanuts; or related to other things in the environment around them, like to the fur of animals. Cannabis is no different, and some people are actually allergic to cannabis, experiencing adverse effects when coming into contact with it.

It has actually been observed that people who have allergies to common foods like tomatoes, peaches, bananas, citrus, eggplant, almonds, and chestnuts may also have an allergy to cannabis, as they are considered cross-reactive because they share similar proteins.

Those who have allergies to the cannabis plant may have it manifest or show up in different ways, including, but not limited to:

• Nasal rhinitis aka. nasal congestion, runny nose, sneezing, and itching in the eyes, nose or throat;
• Allergic conjunctivitis, or swelling of the eyelids and inflammation in the whites of the eyes;
• Asthma, wheezing, or trouble breathing;
• Skin allergies with hives, itching, redness, rash, or dry and patchy skin;
• Drug eruption, or a skin rash that develops as a reaction to some drugs or medications;
• Anaphylaxis, or anaphylactic shock, when there is a severe allergy.

These symptoms may occur with contact with cannabis in any way, including skin contact, airborne allergens, or by consuming the plant by inhalation or edibles.

Why Allergies to Cannabis Occur

Many times in our patient education series, we have talked about the importance of the Endocannabinoid System in cannabis medicine. The endocannabinoid system is the regulator of all bodily systems, however in a cannabis allergy, one system overrides the endocannabinoid system, and that is the immune system.

Allergies occur when your immune system detects something within, entering, or near your body that it perceives as harmful. Acting as the body’s ultimate defense mechanism, your immune system wants those potentially harmful invaders out of the body and will go on to produce antibodies to make your body react. This is why someone with pollen allergies may sneeze in the springtime because the immune system sees pollen as harmful and will produce antibodies and release chemicals like histamines that make you sneeze. In other words, allergies happen when your body thinks something is a harmful invader.

Allergies can actually be hereditary or be caused by changes in the environment around someone, or to their internal immune system. Allergies aren’t necessarily curable, but they can be treated with medications like anti-inflammatories or antihistamines.

In cannabis, it hasn’t been totally isolated what part of the plant causes allergies, but it is believed to be from components of the pollen of cannabis and the smoke. It’s not believed that cannabinoids like THC or CBD are allergens in themselves.

Cannabis Hyperemesis Syndrome (CHS): A Cannabis Lover’s Nightmare

It wasn’t until the early 2000s that Cannabis Hyperemesis Syndrome, or Cannabinoid Hyperemesis Syndrome had a name put to it after it was found that some frequent cannabis users were experiencing severe bouts of vomiting.

In 2004, an Australian study looked at the correlation between Cyclical Vomiting Syndrome and long-term cannabis use, concluding that cannabis caused vomiting in most cases under study. Researchers also saw that people who were frequently and severely vomiting were experiencing abnormal levels of bathing, with the belief that hot water would alleviate their symptoms.

When someone may start feeling the symptoms of Cannabis Hyperemesis Syndrome, it usually begins with morning sickness and chronic nausea that may start years or months before any chronic vomiting occurs. Once the condition worsens, persistent vomiting, nausea, abdominal pain dehydration, and a compulsion to habitually bathe to relieve symptoms are common outcomes. The only way to find relief from Cannabis Hyperemesis Syndrome is to cease use.

This condition is not without its naysayers, however, and those who live with it will often be faced with denial from the cannabis industry who doesn’t believe cannabis can cause negative effects. Those who deny that Cannabis Hyperemesis Syndrome exists posit that the condition has been made up to deter cannabis use in increasingly legalized times, or that it’s not the actual plant that is causing the symptoms, but exposure to chemicals, soil nutrients, or pesticides.

What Do You Do if Allergic to Cannabis?

If you are experiencing negative effects from cannabis, make sure you reach out to Compassionate Clinics of America to discuss with the doctor who provided you your medical cannabis certification. Your doctor will help you determine if or any negative reactions you’re having with cannabis, and why. They may also suggest, if the symptoms are more negative than the positive outcomes of using cannabis, that all cannabis use is completely ceased and alternative treatments are considered.

Cannabis allergy, and Cannabis Hyperemesis Syndrome, are both rare, but something we have to consider when recommending medical cannabis to our patients. While we do believe in the tenets of cannabis medicine, and have seen so many of our patients’ lives change because of it, it is not for everyone.

Reach out to us at Compassionate Clinics of America if you live in Illinois, Pennsylvania, Oklahoma, and Missouri, and discuss whether cannabis medicine is right for you. Make sure you stay tuned to our patient education series as we continue to release valuable information about cannabis medicine that is intended to help our patients make the most of their experience with the powerful plant.