Red eyes can be a classic, telltale giveaway that someone’s smoked weed. For certain people it’s guaranteed to happen and can happen after smoking, eating edibles, and even vaping.

Why it happen in some people and not others can be related to body chemistry, but does it also depend on the quantity or quality of the cannabis consumed?

Why do your eyes get red when you smoke weed?

The cause for reddening of the eyes after smoking cannabis is related to the reason why the plant is famous as a treatment for glaucoma.

In short, THC lowers blood pressure, which in turn causes blood vessels and capillaries to dilate. Ocular capillaries dilate, increasing blood flow to the eyes and reducing pressure in the eye, called intraocular pressure. The increase in blood flow creates eye redness; the corresponding decrease in eye pressure is the benefit that glaucoma patients seek.

Red eyes can still occur even without smoke, such as when eating edibles. It’s not the smoke that makes your eyes red, but the THC.

That being said, it’s also possible for some to have an allergic reaction to cannabis or to smoke in general, which can increase eye redness. A reaction of this nature would likely be universal to smoke and would likely include sensitivity to cannabis, tobacco, and perhaps even incense.

Related

Can cannabis help with glaucoma?

How to to get rid of red eyes from cannabis

Getting red eyes from consuming cannabis is harmless, and as we mentioned above, smoking can actually reduce eye pressure. However, getting red eyes isn’t always welcome. Here are a few steps to take to minimize or reduce eye redness during or after smoking.

• Eye drops. Certain brands are specially formulated to reduce eye redness.
• Stay hydrated. Drinking water can help alleviate dryness in your body.
• Let them run their course. Ultimately, red eyes are not harmful, there just may be some stigma associated with them. Plan smoke sessions for times when you’ll be at home or not in public if you’re concerned about getting red eyes.