does weed make your eyes red

Why does weed make your eyes red?

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  1. Under pressure: lower blood pressure and dilated capillaries
  2. Do edibles make your eyes red?
  3. The redder the better?

Among the most common effects of marijuana use (and telltale signs you’ve recently partaken) is red, bloodshot eyes. It’s to be expected, sure, but that doesn’t answer the mysterious question pondered by generations of stoners: why does weed make your eyes red?

For weed novices, the onset of bloodshot eyes could cause a panic-induced internet search asking “ can smoking weed damage your eyes? ” Thankfully, as those who regularly consume cannabis can tell new users, there are no serious health risks associated with your sudden red-eyed circumstance. You’re probably not experiencing an allergic reaction or some bigger complication. Some might poke fun or chastise you for sporting your so-called “ weed eyes ” in public, but otherwise, it’s a completely natural occurrence that transpires after smoking cannabis.

In fact, your eyes turning red has nothing to do with the act of smoking at all.

Under pressure: lower blood pressure and dilated capillaries

After consuming a cannabis-based product (flower, concentrate, edible, etc.), users generally experience an increase in heart rate and blood pressure. This effect is due to the plant’s cannabinoids, which are chemical compounds responsible for some of the therapeutic and medicinal benefits of cannabis, and their initial interaction with the body. This rise in blood pressure and heart rate is comparable to normal physical activities like exercise or sex.

It generally takes about five to ten minutes for users’ heart rates to return to normal and for blood pressure to begin to decrease. As the blood pressure lowers, the blood vessels and capillaries dilate, including the ocular capillaries . The dilation of ocular capillaries causes increased blood flow to the eyes, which results in your eyes turning red and also reduces intraocular pressure.

The dilation of ocular capillaries causes increased blood flow to the eyes, which results in your eyes turning red in the process, and also reduces intraocular pressure. Photo by: Gina Coleman/Weedmaps

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In fact, according to Dr. Melanie Bone, a board-certified OB-GYN who practices in West Palm Beach, Florida, “It’s cannabis’ ability to reduce intraocular pressure in the eyes that makes it a potentially viable treatment for glaucoma , a group of eye disorders that causes damage to the optic nerves which can eventually lead to blindness. It also happens to explain why your eyes become bloodshot after smoking cannabis.”

Evidence that the THC found in cannabis can lower intraocular pressure (IOP) is a major reason why many glaucoma patients have attempted to use medical marijuana to treat and relieve symptoms of the disease. It’s important to know that some studies have contradicted or added a caveat to the claim that cannabis is beneficial for glaucoma. For instance, a 2018 study conducted at Indiana University found that cannabidiol (CBD), the non-intoxicating cannabinoid found in marijuana, could potentially worsen the condition by increasing eye pressure . More research into the use of cannabis for glaucoma treatment is needed.

Do edibles make your eyes red?

Similar to smoking cannabis, ingesting edibles could also make your eyes turn red. Again, this depends on the amount of THC consumed. Remember, it’s not the smoke itself that makes your eyes red, but rather the ability that cannabinoids have to lower blood pressure, causing blood vessels and capillaries to dilate.

The redder the better?

The amount your blood pressure is lowered and how red your eyes become depends on the amount of THC you consume.

Tetrahydrocannabinol (THC), the most common cannabinoid in the plant, is responsible for the intoxication associated with smoking cannabis. The greater the concentration of THC in a cannabis product, the stronger the effects and the redder your eyes become.

The greater the concentration of THC in a cannabis product, the stronger the effects and the redder your eyes become.

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So, red eyes can act as a sign that your cannabis has a high cannabinoid content (i.e., it’s potent). In other words, if your eyes are noticeably bloodshot after consumption, there’s a good chance you’ve landed yourself some highly potent weed.

Other than being a dead giveaway that you’ve recently consumed cannabis, you have no reason to be concerned about the redness of your eyes. Cannabis-induced eye redness will typically only last a few hours and can easily resolve if you have the right tools at your disposal.

It isn’t a bad idea to have eye drops (or some sunglasses) on hand. Look for eye drop brands that are specifically designed to reduce eye redness. There are other methods that could potentially help combat cannabis-induced bloodshot eyes, including staying hydrated, washing your face and eyelids with cold water, or simply consuming cannabis products with lower THC levels.

Ever wonder why using marijuana or cannabis makes your eyes red or bloodshot? Discover why weed gives you bloodshot eyes.

Ask Cheri

Dear Cheri,

Am I going crazy? My eyes always get red after smoking marijuana, but other day I did not smoke at all although I did eat a marijuana brownie. My eyes were red the same way they are after smoking. What’s going on? I always assumed it was irritation from smoke that made your eyes red. So my question is why does weed make your eyes red and do edibles make your eyes red? OK, that’s two questions. Thanks in advance for your insight and all your great educational content, I have learned so much from you already.

Awww, thank you for your kind words. OK, quick answer, no you are not going crazy. at least not because of this.

To be sure different people have different sensitivities to the red eye phenomenon, but first and foremost having red eyes after using marijuana is not dangerous and might even be beneficial.

Believe it or not, how much your eyes turn red can have a lot to do with the amount and quality of the herb you are consuming, regardless of how you consume it.

That’s right it does not matter if you smoke cannabis, vape it, or eat infused edibles, these ingestion methods can ALL result in red eyes.

That’s because it is not the smoke in marijuana that causes redness but rather the THC. So you were not imagining your red eyes after consuming a pot brownie.

The reason THC turns your eyes red is the same reason cannabis can be effective as a glaucoma treatment, namely it lowers intraocular pressure.

This happens because THC reduces blood pressure and dilates capillaries. When ocular capillaries dilate that increases blood flow to the eyes and creates redness.

Likewise, a strain that has a higher THC content is likely to make your eyes redder than one with low THC.

How to Reduce Red Eyes

Even though red eyes after using cannabis is not harmful, there are definitely occasions when you might not want to to be broadcasting this telltale clue that you’ve just had an encounter with “Mary Jane.”

So is there anything you can do to reduce red eyes?


  • Eye drops, especially those formulated to reduce red eyes can definitely help, especially if you need fast relief.
  • As we have already discussed, less THC means less redness so you should likewise save your potent top shelf for later if you are trying to avoid red eyes. In fact, this is a good time to break out the CBD.
  • It’s questionable at best whether drinking water actually helps with eye redness, despite this frequently repeated advice. That said drinking water is good for you, most people don’t get enough, it can fight eye dryness (a secondary cause of redness), and it also counteracts marijuana’s other annoying side-effect, cotton mouth. So I say drink up!

Why does weed make your eyes red? Can edibles make your eyes red? Can you do anything to reduce eye redness? Get the answere here. ]]>