Fraser Horton
Fraser Horton
Last Updated on October 7, 2021

We’re sure you would agree that getting red eyes after smoking weed is a dead giveaway of your activity that maybe you’d prefer to keep to yourself. Sure, smoking weed is great, but it makes your eyes red and no one likes that.

This common side effect is all too familiar to everyone in the community, casual and medical marijuana users alike, and managing to avoid it or lessen its appearance is always very satisfactory. So, let’s discuss all about it including its causes, and we’ll give you some tips on what you can do to avoid this.

What Happens When You’re Smoking Weed?

When weed enters the body, it immediately starts attaching to the body’s own cannabinoid receptors which are part of the endocannabinoid system. These receptors are located in various places throughout the body, including the nervous system and the brain, and they’re part of a network that takes part in many vital processes in the body. The main cannabinoids in weed, THC and CBD, bind to these receptors and influence the body in various ways.

Why Do You Get Red Eyes?

Believe it or not, the smoke from weed isn’t the main cause of getting bloodshot eyes. Instead, the main cause of “weed eyes” is THC. When THC comes into contact with the endocannabinoid receptors in your body, it causes the blood pressure to temporarily increase, and with that, your heart rate increases as well. This is when you feel the initial rush of endorphins after you first inhale.

However, after a short while, your heart rate begins to gradually go down, back to normal. After no more than 15 minutes, as your blood pressure decreases, your blood vessels start to dilate. This causes an increased blood flow through your whole body, including your eye area. The result – very prominent ocular capillaries, or in other words, the good ol’ red eyes.

Will Everyone Get Red Eyes?

Most people do get bloodshot eyes when smoking cannabis. However, the severity of it will vary from person to person due to many different factors. First, long-term users of marijuana will probably be more immune to getting red eyes because their body is more used to THC and its effects, unlike casual users or newbies, who will definitely be redder in the eye area after smoking.

Some people may be more naturally prone to getting red eyes, not just from the THC in weed, but also from various things, like allergies, pollution, catching a cold, having a migraine, and various other things that can cause this reaction.

Getting red eyes can also depend on the strain you’re smoking, and not just the amount of THC. The cannabis plant has hundreds of different strains, each with its own combination of cannabinoids, terpenes, and flavonols in varying concentrations that interact together synergically. So, some strains will probably be more likely to make your eyes look like red roses. There is no way you can know for sure in advance unless you try and see it for yourself.

The One Upside

The one upside to this side effect of THC is that it’s actually really helpful for glaucoma patients. Glaucoma refers to a group of eye disorders where the nerve at the back of the eye called the optic nerve is damaged, which can lead to complete loss of vision over time. Glaucoma patients usually have an increased pressure in their eyes called intraocular pressure, the pressure-reducing effect of THC is quite relieving. Therefore, not everyone dreads getting red eyes, as for some it means relief.

Can You Do Anything About It?

Smoking marijuana may come with a lot of perks, but most everyone would agree that getting red eyes is not one of them. However, there may be some little ways you can help yourself to prevent them next time or at least reduce the redness.

Vasoconstrictors Are Your Best Friends

Vasoconstriction means the shrinking of blood vessels, therefore, you’ll need something that causes blood vessels to shrink. Your best choice is eye drops that contain the active ingredient Tetryzoline, which is great for reducing the blood flow to the eyes, causing vasoconstriction. If you smoke weed regularly, you’ll definitely need to have these eye drops near you.

Other vasoconstrictors are, believe it or not, dark chocolate, cola, or coffee. All of these three contain caffeine in some form or another, and caffeine is known for being able to shrink the blood vessels by increasing blood pressure. So, if you don’t have any eye drops, any of these beverages or chocolate may just do the trick for you.

Don’t Skip on Hydration

This will sound basic, but if you don’t drink enough water, you will probably be more susceptible to getting red eyes and you will generally be more uncomfortable. Simply, you don’t want to give your body more reasons to experience discomfort. So, keep your fluid intake in check as part of the prevention process for eye redness, plus it’ll help with cottonmouth.

The Colder the Better

Cold temperature is the most natural vasoconstrictor. Simply, splash your face with cold water a few times after marijuana use, as cold as you can bear, or you can even take a cold shower if you really need to get rid of the redness more efficiently. Alternatively, you can wrap some ice cubes in a towel and put them over your eyes for about 15 seconds at a time. It may not reduce the redness completely, but it will make a big difference.

Low THC, High CBD

To avoid getting bloodshot eyes, a good choice would be to smoke strains that are low in THC and high in CBD. They may not be your favorite ones, but for days when you want to relax and enjoy a doobie, but also have errands to run and stuff to do and you don’t want to risk getting red eyes, low THC strains may become your go-to. Fast Eddy, Lemon Tree, and Granddaddy Purple are some great low THC choices you can look up.

Make a Designated Schedule

If you don’t want to give up your favorite high THC strains, then you can just plan your smoke session ahead on days when you know you don’t have that much stuff to do and just spend the rest of the day relaxing without worrying about anyone noticing your red eyes.

Alternatively, Wait it Out

If you have time, just wait it out. In most cases, bloodshot eyes start to subside after about 3 hours, so you can give it some time, splash some water, and then move on with your day as usual.


Getting red eyes is a very common side effect of cannabis use. The reason behind it is the effect of THC on heart rate and blood pressure, which causes the blood vessels to dilate. This is most noticeable in the eyes as they are a delicate area. However, glaucoma patients get some benefit from it as it offers some eye pressure relief.

You can alleviate this effect by using eye drops or drinking a caffeinated drink, as well as using a cold compress. If you want to avoid getting bloodshot eyes, you can also choose to smoke a low THC strain, or smoke on days when your schedule is clear.


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