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Why Does Cannabis Make Your Eyes Red?

Updated August 20, 2022

Most people who have smoked cannabis or know anyone who did are familiar with the fact that it makes your eyes red. It is common for people to experience red eyes following cannabis use. Many people have been caught smoking due to their red eyes. There is a perfectly logical explanation for the red eyes associated with smoking cannabis. There are even some useful tricks to minimize the red eyes or get them to disappear more quickly.

You May Be Dehydrated

If you are dehydrated, then your eyes will broadcast your cannabis use by turning red. Certain strains of cannabis can cause excessive thirst or dry mouth.

The solution to preventing red eyes, for this reason, is simple: drink enough water. If you plan on smoking cannabis later on in the day, make sure to drink plenty of fluids during the day. While you are smoking, keep some water nearby so you can stay hydrated as needed. Avoid caffeinated or carbonated drinks, as they will worsen your dehydration, keeping your eyes red.

Do not worry if you find yourself drinking more water when smoking cannabis than usual. This is natural, especially if you smoke a strain that causes thirst. Just remember that there is such a thing as drinking too much water. However, as long as you do not force yourself to drink more than you feel comfortable drinking, you are unlikely to reach that point. When working to stay hydrated, opt for room temperature water when possible. It will keep you hydrated and fight the red eyes better than cold water.

Your Blood Pressure May Be Lower

It is common for the THC in cannabis to lower your blood pressure. This means that your blood vessels dilate, with more blood flowing through them. When your blood pressure drops, you will get red eyes, regardless of how you consume cannabis.

The red eyes occur due to the ocular globes in your eyes. These will expand when you used cannabis, letting the blood circulate so that it is visible. This can create a red appearance.

This Can Be Good for Some People

When it comes down to it, most people who experience red eyes from cannabis do so due to a reduction in intraocular pressure. This is a good side effect of cannabis for those with glaucoma. Glaucoma is vision damage and eventual blindness due to high intraocular pressure. By temporarily relieving that intraocular pressure, cannabis can slow down the progression of glaucoma.

You May Be Allergic

Although this is not typically the reason behind the red eyes, some people are allergic to cannabis. This only applies to a small percentage of the population, and the symptoms of an allergy can vary.

In most cases, if you get red eyes due to a cannabis allergy, you will have other symptoms as well. You will also notice other allergy-related symptoms, like swelling, itchy skin, and hives. If you are allergic to cannabis, you may want to consider the severity of your reaction before deciding to use it again in the future. Remember that allergies can worsen with repeated exposure, so this is something to consider when making a decision.

The Strain May Cause Red Eyes

It is also worth noting that the cannabis strain you choose may influence whether your eyes turn red. Some strains are highly unlikely to give you red eyes while others are more likely to do so. It is also possible that your body will begin resisting the increased blood flow, so your eyes no longer turn red.

Red Eyes May Be Inconsistent

Getting rid eyes from smoking or using cannabis is interesting as you may not get them, and it may not occur every time. Some people always get red eyes after smoking while others never do. Some will only get red eyes when smoking certain strains of cannabis. Some people may only notice red eyes in seemingly random instances.

You should not be concerned if your eyes get red from using cannabis one day even though you typically don’t. You should also not worry if the opposite is true. Remember that reactions can vary between people and between events. Just some of the factors that can impact how red your eyes become include frequency of consumption, overall health, genetics, sex, and the cannabis strain.

Red Eyes From Smoking Vs. Edibles Vs. Other Ingestion Methods

No matter how you choose to ingest cannabis, your eyes may turn red. This means you will get red eyes whether you smoke cannabis, eat edibles, or use cannabis oil. After all, the red eyes are not from the act of smoking; they are from the THC’s ability to reduce your blood pressure.

Degrees of Redness

Since the main cause of red eyes from cannabis is low blood pressure, the extent to which you experience a reduction in blood pressure will determine how red your eyes are. The extent to which your blood pressure drops depends on how much THC you have. This means that if you consume more THC, your blood pressure will drop lower, resulting in redder eyes.

THC is also the component of cannabis responsible for its psychoactive effect or potency. This means that if your eyes get very red after using cannabis, this is probably a good indication that it is potent marijuana.

How Long It Lasts

Everyone is different, but in most cases, your eyes will not stay red for more than a few hours after using cannabis.

How to Relieve Red Eyes From Cannabis

If you do not like to have red eyes after using cannabis or do not want others to discover you used it from your eyes, there are a few solutions.

Eye Drops

The most common method of returning your eyes to their normal color after smoking cannabis is to use eye drops. Be sure to grab traditional eye drops and stay away from allergy eye drops. Feel free to use allergy eye drops if you have an allergy, but if you do not have one, they can irritate your eyes as well. Some people do suggest using allergy drops for this purpose, but the risk of irritation may worsen your red eyes.

Don’t Rub Your Eyes

You can prevent red eyes and make them get back to normal more quickly by avoiding touching them. Rubbing your eyes will typically worsen the redness, which is the opposite of your goal.

Stay Hydrated

Since the red eyes may be due to dehydration when smoking, you can prevent them and speed up their return to normal by staying hydrated. At the very least, ensuring you are hydrated will reduce your chances of getting red eyes.

Wear Sunglasses

If you go outside during or after using cannabis, use sunglasses to protect your eyes from the sun. This may not directly reduce the redness, but it will help your eyes’ overall health. Your chances of eye damage from the sun increase when the blood vessels are visible so that this simple precaution can protect your eyes from damage.

Consume Something to Constrict Blood Vessels

Since the red eyes are due to relaxed blood vessels, you can counter this by consuming something that will constrict your blood vessels. Options include sodium, caffeine, licorice, and chocolate.

Washing Your Face With Cold Water

Some people have found success in getting rid of the red eyes from cannabis use by simply washing their faces with cold water. For this method to work, make sure you also get your eyelids wet with the cold water.

Opt for Lower THC Levels

You can also plan ahead of time and reduce the extent of your red eyes by choosing cannabis with a lower THC content. This should result in a reduced difference in blood pressure and therefore, less red eyes.

Just Wait

The best method to relieve cannabis-induced red eyes is to wait. If you can, plan on using cannabis at a time when you do not need to have clear, non-red eyes for several hours at least. This is also a smart way to ensure you will not be too high to participate in your planned activities.

The Red Eyes Do Not Indicate Anything Serious

The most important thing to keep in mind about the red eyes you get from smoking cannabis is that it is not serious. This is a natural result of marijuana and nothing you should be concerned about. You do not need to worry about permanent damage to your eyes from the redness or make a doctor’s appointment to take care of the problem.

The exception to this rule will be if you notice other symptoms in addition to the red eyes. If, for example, you also have hives, you are probably one of the unlucky few with a cannabis allergy and should reconsider using it in the future.

What Else to Expect When Using Cannabis

In addition to the red eyes, what else can you expect when you smoke or otherwise use cannabis? Your reaction will depend on personal factors like your frequency of use and body chemistry, as well as situational factors like the strain and the quantity ingested. The following are some of the more common things that people experience when using cannabis.

Heightened Senses

It is very common to experience heightened senses when you smoke cannabis. This may include colors seemingly brighter or music sounding better.


Feelings of hunger are very common when using cannabis; hence, the term “the munchies.” You may want to keep some snacks on hand if you plan on smoking cannabis.

Changes to Levels of Socialness

Some people get more talkative when they consume marijuana, while others get the giggles and cannot stop laughing.

Changes to Relaxation and Anxiety

You may also experience changes to your levels of anxiety and relaxation. Many people feel more relaxed when smoking cannabis, but some feel more anxious or even afraid.

Changes to Time

Sometimes, using cannabis can lead to a feeling that time has slowed down.

Reduced Reaction Time

Cannabis will almost always slow down your reaction times, even if you do not feel like it at the time. This is important to remember since it means you should not drive while “high.” Your reaction times will be slow, dramatically increasing your chances of getting into a car accident.

Relief From Symptoms Like Pain and Nausea

For those who suffer from pain and nausea on a regular basis, you should expect to experience a reduction in those problems when you consume cannabis. There is plenty of evidence that shows cannabis can relieve chronic pain and nausea, including symptoms caused by chemotherapy to treat cancer. Those are some of the main reasons that medical marijuana has become so popular, as has CBD, the non-psychoactive cannabinoid in cannabis. Cannabis may also relieve seizures and help those with insomnia fall asleep and stay asleep.

When You Have Too Much

If you start to feel dizzy, anxious, or nauseous from consuming cannabis, then you should slow down your consumption. These effects indicate you consumed too much and are mellowing down. You can probably wait out the feelings or counter them to some extent with a sugary beverage, laying down somewhere quiet, or smelling something strong, like peppercorn, cloves, or tart lemon.

Those who are not used to cannabis may also feel sick or faint the first few times they use it.

If You Don’t React

In the case of those who are new to cannabis, some feel as if they did not react at all. In most of these cases, it was because they do not pull the cannabis smoke into their lungs properly. Once you master the smoking technique, you will see better effects.


For most people, cannabis will make your eyes red because it lowers your blood pressure. This results in reduced intraocular pressure, meaning the blood vessels in your eyes become more visible, giving that red appearance. The effect is not harmful in any way and should go away in a few hours.

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