Can your eyes get red from being buzzed? The physiological truth

October 1, 2025 •

4 min read

When consuming certain substances, your body's blood vessels, including the tiny capillaries in your eyes, can undergo significant changes. Understanding this physiological reaction is key to answering the question, “Can your eyes get red from being buzzed?” as it is a common yet often misunderstood effect.

Quick Summary

Yes, red eyes are a common effect of being buzzed, caused by vasodilation, the expansion of blood vessels in the eyes. The underlying mechanisms differ depending on the substance, involving factors like dehydration for alcohol and lowered blood pressure for THC, and are typically temporary.

Key Points

Vasodilation is the Cause: Both alcohol and cannabis (THC) cause blood vessels in the eyes to dilate, making them appear red.
Alcohol's Dehydration Effect: Alcohol contributes to red eyes by causing dehydration, which leads to dryness and irritation in the eyes.
THC Lowers Blood Pressure: The active compound in cannabis, THC, lowers blood pressure, leading to the expansion of ocular capillaries and subsequent redness.
Consumption Method Doesn't Matter: Red eyes from cannabis are caused by THC in the bloodstream, so edibles and smoking can both lead to the same effect.
Redness is Temporary: For both alcohol and cannabis, the red-eye effect is typically temporary and subsides as the substance is metabolized by the body.
Other Causes Exist: Allergies, fatigue, and other eye conditions can also cause redness, so substance use isn't the only possible explanation.
Alleviation Methods: Simple remedies like eye drops, hydration, and cold compresses can help reduce redness.

The Science Behind Red Eyes from Alcohol

Drinking alcohol can lead to red, bloodshot eyes due to two main physiological processes: vasodilation and dehydration. Alcohol acts as a vasodilator, causing the blood vessels throughout your body to expand or widen. In the delicate, transparent sclera (the whites of your eyes), this effect is highly visible as the tiny capillaries become enlarged and carry increased blood flow, giving them a distinct reddish appearance.

Vasodilation and Blood Vessels

When alcohol enters your system, it increases blood flow to the eyes, which can be seen as redness. This effect is a temporary change caused by the substance's impact on your body's circulation. It is not necessarily indicative of severe harm but is a clear sign that the alcohol is affecting your body's systems.

Dehydration's Impact on Eye Irritation

Alcohol is also a diuretic, meaning it promotes the loss of fluids from your body, which can lead to overall dehydration. This dehydration can affect the eyes, causing them to become dry and irritated. When your eyes lack proper moisture, they can appear red, glassy, or shiny. This dryness can exacerbate the redness already caused by vasodilation.

The Science Behind Red Eyes from Cannabis (THC)

The main reason cannabis, specifically the compound THC, makes your eyes red is its effect on blood pressure. THC acts as a vasodilator, but it does so by lowering overall blood pressure. This drop in blood pressure causes blood vessels to dilate, including the ocular capillaries in your eyes. The increased blood flow to these capillaries makes them more visible, resulting in the characteristic red eyes.

THC as a Vasodilator

The dilation of blood vessels is a direct result of THC's interaction with the body's endocannabinoid system. For this reason, it can also decrease intraocular pressure, which is why cannabis has been explored for medical uses in conditions like glaucoma. The amount of redness experienced is often directly correlated with the THC concentration and an individual's tolerance.

Edibles vs. Smoking: Is there a difference?

Many people wonder if the method of consumption affects eye redness. It's a common misconception that smoke from smoking irritates the eyes and causes redness. However, the redness is caused by THC in the bloodstream, not the smoke itself. This means that consuming edibles with THC can also lead to red eyes, though the onset might be slower because the THC must be processed by the liver before entering the bloodstream. For smoking or vaping, the effect is more immediate as THC enters the bloodstream through the lungs more quickly.

What Else Can Cause Red Eyes?

While being buzzed is a common cause, many other factors can lead to red eyes. Providing a comprehensive overview is essential for proper health awareness. Other potential causes include:

Allergies: Allergic reactions can cause eye irritation and redness.
Eye Strain: Staring at a computer screen or driving for long periods can cause fatigue and redness.
Dry Eye Syndrome: Chronic dryness can lead to persistent eye redness and discomfort.
Infections: Conditions like pink eye (conjunctivitis) cause inflammation and redness.
Contact Lens Issues: Extended wear or improper cleaning can lead to irritation.
Environmental Factors: Exposure to smoke, dust, or other irritants can cause redness.

How to Alleviate Red Eyes After Being Buzzed

If you find your eyes are red after consuming alcohol or cannabis, there are several things you can do to help reduce the redness and discomfort. Here are some practical steps:

Use Over-the-Counter Eye Drops: Medicated eye drops designed to reduce redness contain vasoconstrictors that help tighten the dilated blood vessels in the eyes, temporarily reducing the redness.
Stay Hydrated: Drinking plenty of water is crucial, especially when consuming alcohol, to combat dehydration and reduce eye dryness and irritation.
Apply a Cold Compress: Placing a cold compress over your eyes can cause blood vessels to constrict, helping to diminish the redness.
Take a Break from Contacts: If you wear contact lenses, taking them out and wearing glasses can give your eyes a rest and reduce irritation.
Consume a Low-THC Strain: For cannabis users, opting for a strain with lower THC concentration can significantly reduce the likelihood and intensity of red eyes.
Try Caffeine: The vasoconstrictive effects of caffeine may help to temporarily reduce the appearance of redness.

Alcohol vs. Cannabis: Side Effects Comparison Table


Feature	Alcohol Consumption	Cannabis (THC) Consumption
Cause of Redness	Vasodilation from increased blood flow and dehydration.	Vasodilation from decreased blood pressure.
Other Eye Effects	Glassy eyes, slower pupil response, droopy eyelids.	Potential for dry eyes, though less common than redness.
Duration of Redness	Varies, typically lasts a few hours after consumption.	Varies based on dosage and metabolism, can last up to a few hours.
Contributing Factor	Dehydration plays a significant role in causing dryness and irritation.	THC concentration is the direct cause, not smoke.

When to See a Doctor About Red Eyes

While temporary red eyes from being buzzed are not usually a cause for concern, there are instances where you should consult a doctor. If the redness persists for an unusually long time after the effects have worn off, or if it is accompanied by pain, vision changes, increased light sensitivity, or persistent dryness, it could signal an underlying issue that needs medical attention. Yellowing of the eyes, a sign of jaundice, requires immediate medical attention.

Conclusion

In summary, red eyes are a common side effect of being buzzed, whether from alcohol or THC, and the root cause lies in the physiological effect of vasodilation. Alcohol-induced redness involves vessel expansion and dehydration, while THC's effect is primarily due to a drop in blood pressure. Though usually temporary, being aware of these mechanisms can help you understand the impact substances have on your body. For a deeper scientific look at alcohol's systemic effects, including its impact on vision, you can explore resources like the National Library of Medicine, which hosts various studies on the subject.

Frequently Asked Questions

No, not everyone who drinks will get red eyes. The severity of the effect depends on individual tolerance, the amount of alcohol consumed, and overall hydration levels.

The duration of red eyes depends on the substance and the amount consumed. Alcohol-related redness usually fades within a few hours, while THC-induced redness can last for one to four hours, depending on dosage.

Yes, edibles can cause red eyes. The redness is caused by THC in the bloodstream, not by smoke irritation. Since edibles take longer to be processed, the onset of redness might be delayed compared to smoking.

You can use eye drops designed for redness relief or apply a cold compress to help constrict blood vessels. Staying hydrated is also key. For discreetness, wearing sunglasses is an option.

Products containing only CBD (Cannabidiol) are less likely to cause red eyes than those with THC. Red eyes are specifically linked to THC's effect on blood pressure, not CBD.

For most people, temporary red eyes from moderate consumption are not dangerous. However, persistent redness or other symptoms could indicate an underlying issue, and excessive chronic use can lead to more serious eye problems.

No, red eyes are caused by the THC compound, not the smoke itself. Any method of consumption, including vaping or edibles, can cause redness if it contains THC.