Why Does Marijuana Make Your Eyes Red?

Cannabis contains the main psychoactive ingredients responsible for widening the blood vessels behind your eyes. THC is a kind of cannabinoid known as tetrahydrocannabinol. The receptors in your body, particularly those in the eyes, are connected to cannabinoid receptors.

The red appearance of your eyes is caused by the dilation and increased blood flow in the capillaries in your eye. Hence, people refer to this condition as bloodshot eyes.

In addition to widening ocular capillaries, the THC also temporarily reduces intraocular pressure in glaucoma patients. Basically, glaucoma is caused by increased intraocular pressure, ultimately damaging the optic nerve, and causing vision loss. 

Glaucoma treatment aims to reduce this pressure. It has never been proven that marijuana can treat cataracts, although they may come together naturally with glaucoma. Therefore, if you have glaucoma combined with cataracts, you may require cataract surgery.

Why Does Marijuana Cause Red Eyes?


As the primary psychoactive chemical in marijuana, tetrahydrocannabinol (THC) causes vasodilation behind the red eyes. One hundred thirteen different substances, collectively known as cannabinoids, make up marijuana. Among them, THC is just one. These compounds bind to cannabinoid receptors in all parts of your body, including your eyes.

The action of THC on cannabinoid receptors lowers our blood pressure, causing blood vessels and capillaries to dilate or expand. 

The following explanation should provide insight into whether edibles cause your eyes to redden. Edibles may also cause red eyes via vasodilation since THC is also in them, like topicals and tinctures.

During the treatment of glaucoma, the vasodilation of ocular capillaries caused by THC also decreases intraocular pressure. 

Treatment of glaucoma should therefore focus on reducing this pressure. According to one study, smoking marijuana can reduce intraocular eye pressure by as much as 30%.

Other Factors Affecting Red Eyes

There’s no guarantee that red eyes mean someone has been smoking marijuana, but it’s a strong indicator. THC levels vary among marijuana strains, which is why multiple strains cause multiple effects. As a result, someone who consumes a high-THC strain may suffer from severe red eyes but hardly realize the impact while ingesting a low-THC strain.

There are, however, more factors at play than the THC content alone. Different strains of cannabis can affect individuals differently, as you may have experienced yourself. There is a wide range of personal effects because of gender, genetics, and health factors.

Blood pressure is the primary factor in determining whether or not a person experiences red eyes. THC lowers blood pressure to the point of causing severe bloodshot eyes in high blood pressure patients. The possibility of red eyes is low or next to zero in those with naturally low blood pressure.

However, it is essential to bear in mind that people with marijuana allergies or allergies to smoke, in general, may experience exacerbated symptoms. A typical user with marijuana allergies does not experience red eyes as a result of their allergies.

Marijuana Smokers’ Red Eye Remedy

eyesThe redness of the eyes due to marijuana is completely harmless and usually isn’t a problem. Nevertheless, they can be a nuisance, especially for people who require cannabis to keep their day going. 

Bloodshot eyes can cause unwanted attention and legal questions when attending work or university due to the stigma associated with marijuana. By following a few simple strategies, bloodshot eyes caused by marijuana can reduce in severity.

  • Treat with Eye Drops

The most effective means of curing red eyes are over-the-counter eye drops for allergies, redness, and itching. Tetryzoline is an alpha-agonist, which constricts blood vessels, and is found in all types of eye drops HC-induced dilations reverse the effects of THC. It works to lower blood flow to the eyes and helps reduces their redness.

  • Home Remedies

In addition to the over-the-counter eye drops, there are other items you might have that will cause the blood vessels to constrict. For instance, caffeine can also cause constriction of blood vessels when consumed. In this case, drinking a few squares of dark chocolate or drinking a fresh cup of coffee might help quench the redness.

Coldwater is also a potent vasoconstrictor. Our bodies send blood toward our vital organs during this period to protect them. This can be accomplished by letting cold water run over your face or by applying an ice pack to your eyes.

Does Everyone Experience Red-Eye After Taking Marijuana?

cbdWhen smoking cannabis, most people experience red eyes. The complexity of the problem can differ from one individual to another because of various factors. Cannabis users who have been using it for a long time will be more likely not to suffer from the red-eye syndrome. Due to their body’s acclimatization to THC effects, they experience more minor side effects than newbies.

It is not just the amount of THC that affects your eyes but also the strain you smoke that may cause symptoms like bloodshot eyes. Many strains of the cannabis plant may cause your eyes to become redder since the plant contains so many varieties. Other factors can also cause red eyes in some individuals, such as allergies, catching a cold, pollution, experiencing a migraine, etc.

However, if you are expecting to work the next day or have school, it is best to avoid taking marijuana for some time to avoid unnecessary attention. You can also use the remedies timely to ensure the redness has disappeared before going out of the house.


When you use cannabis, you are likely to experience red eyes. THC dilates the blood vessels by affecting blood pressure and heart rate. As sensitive parts of the body, the eyes will inevitably suffer from this effect. There are, however, some benefits to glaucoma patients as it lowers their eye pressure.

Using eye drops, drinking caffeinated beverages, or applying cold compresses can help ease this effect. You can likewise avoid getting red eyes by choosing a low THC strain or by smoking when you have time on your hands. 

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