Why Cannabis Causes Red Eyes (And What To Do About It)

Red eyes have long been associated with stoners, and are the go-to telltale sign that someone has been smoking cannabis. It’s definitely something most smokers are conscious of, as there are often negative social connotations that come with it. It can be especially risky in countries that legally frown upon the use of cannabis.

If you happen to be one of those self-aware stoners, you might wonder: “How does it happen? How can I fix it? Can I avoid it?”. We’re here to put you at ease with answers to all these questions.

WHAT CAUSES RED EYES?

While there is no single, definitive reason behind the cause of red eyes, there are a few different factors. When combined, you’ll be looking as stoned as ever.

BLOOD PRESSURE CHANGES

One of the main causes of red eyes is the drop in blood pressure experienced when ingesting cannabis. As you might know, your blood pressure and heart rate initially rise when smoking. However, after some time, the cannabinoids begin to lower your blood pressure. In turn, they dilate your blood vessels, including the ones in your eyes.

EXPOSURE TO SMOKE

If you choose to smoke your cannabis, the smoke exposure itself may be another reason you get red eyes. Especially if you smoke in an unventilated area, it’s not uncommon for the eyes to get agitated. If you stay in that space long enough, you’ll eventually notice your eyes getting red and sore.

DEHYDRATION

Dehydration also plays a significant role in getting red, bloodshot eyes. Being dehydrated will cause your eyes to become dry and irritated, making them appear red in turn. While cannabis does not actively dehydrate you, your body uses water to remove THC from your blood. That, of course, will play a part in dehydrating you as well.

HOW DO DIFFERENT CONSUMPTION METHODS AFFECT RED EYES?

So, do different consumption methods affect whether your eyes get red, or how red they get? There aren't serious differences, but there's more nuance to the distinctions than you might think.

SMOKING

This method of ingestion introduces all three factors: exposure to smoke, dehydration, and lowered blood pressure. Considering that, red eyes seem like a pretty inevitable side effect when smoking weed the old-fashioned way.

VAPING

Similar to smoking, vaping is a surefire way to get red eyes. While there’s no actual smoke involved in vaping, the fact that most cannabinoids are preserved means you’re getting more potent hits. That means more THC in your bloodstream, which leads to dehydration, lowered blood pressure, and, eventually, bloodshot eyes.

EDIBLES

As we’ve implied, how you consume your cannabis doesn’t make a big difference in whether you’ll get red eyes or not. Edibles won’t produce any smoke unless you’re a terrible baker, so that won’t be a contributing factor. You can, however, accidentally consume more cannabis than you normally would if you aren’t watching your intake.

Lowered blood pressure will also come into play, which’ll explain your very red eyes. Although counterintuitive, potent edibles can actually be one of the biggest culprits of super-red eyes.

TRANSDERMALS AND TOPICALS

Yes, even transdermal products containing THC will still give you red eyes. Once the THC has been absorbed into your body, it will cause the same reaction as smoking or vaping. Your blood pressure will eventually drop, causing your capillaries and blood vessels to dilate.

Don’t confuse transdermal products with topicals, though. The latter, which refer to infused lotions and similar products, won’t give you red eyes. However, that’s only because they don’t get you high.

HOW TO TREAT RED EYES

Just because your eyes get red doesn’t mean they’ll stay like that forever. Here are a few suggestions on how to treat those bloodshot marbles.

HYDRATE

Being dehydrated will make your eyes dry and irritated before you’ve even had the chance to smoke. As classic wisdom will confirm, it’s essential to stay hydrated and drink lots of water. This will not only help your eyes, but will also curb cannabis’ other negative side effects, like cotton mouth.

USE EYE DROPS

If your eyes are prone to getting dry and irritated, eye drops could make all the difference. Keeping your eyes lubricated can act as a natural defence against smoke, along with making your eyes less bloodshot. Personally, we recommend Open Your Eyes, a product engineered especially for those prone to red eyes.

Open Your Eyes

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WEAR SUNGLASSES

No, it isn't an actual treatment for red eyes. But that being said, why don't you just put on a pair of sunglasses?

It sounds silly, but it works in a pinch if you need to go out and you’re self-conscious about looking high. Unless you walk into an indoor work meeting with shades on, the fact that you’re toasted will be your little secret!

CAN YOU PREVENT RED EYES?

Well, there’s no definitive way to prevent red eyes, but there are steps you can take to avert them. Your main option, of course, is smoking strains with less THC. Now, you might have preferences for stronger strains, but if red eyes are an issue, you should try a milder option to see how it suits you. Thankfully, we’re familiar with some quality low-THC options you could give a shot! Other than that, it’s just a matter of treating red eyes with the options listed above, or simply waiting for your eyes to return to normal.

ARE RED EYES BAD?

The short answer is no; it’s just a natural side effect of enjoying cannabis. From a physical perspective, there is no need for alarm, and the effects wear off over time. It’s only from a social standpoint that some may feel bloodshot eyes aren’t acceptable. Just make sure you’re staying hydrated, and keep a bottle of eye drops nearby if you need to look sober. And again, remember that some people, like those with intraocular pressure, might actually benefit from red eyes caused by cannabis!

Adam Parsons

Professional cannabis journalist, copywriter, and author Adam Parsons is a long-time staff member of Zamnesia. Tasked with covering a wide range of topics from CBD to psychedelics and everything in between, Adam creates blog posts, guides, and explores an ever-growing range of products.

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