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Why Does Marijuana Make Your Eyes Red?

Why Does Marijuana Make Your Eyes Red? - Empire Rolling Papers

Why Does Marijuana Make Your Eyes Red?

Please note that while Empire Rolling enjoys exploring topics like these, we are not medical professionals, and this post is not medical advice.

For many people, one of the most iconic signs of using marijuana is red, bloodshot eyes.

This noticeable change in eye appearance has led to countless jokes and stereotypes, but have you ever wondered why marijuana makes your eyes red?

In this blog post, we'll delve into the science behind this phenomenon and explore the factors that contribute to those telltale red eyes.

Why Does Marijuana Make Your Eyes Red?

Dilation of Blood Vessels

One of the primary reasons marijuana causes red eyes is the dilation (widening) of blood vessels, including those in the eyes.

When you consume cannabis, the active compounds, particularly delta-9-tetrahydrocannabinol (THC), interact with cannabinoid receptors throughout the body, including in the eyes.

This interaction results in the relaxation of blood vessel walls, causing them to widen. This vasodilation leads to increased blood flow throughout the body, including the blood vessels in the eyes.

Lowered Blood Pressure

Marijuana can also lower blood pressure, and this drop in blood pressure contributes to the redness of the eyes.

When blood pressure decreases, it can cause blood vessels, including the tiny blood vessels (capillaries) in the whites of the eyes (sclera), to dilate further. As a result, the redness becomes more pronounced.

Dry Eyes

Another factor that contributes to red eyes is dryness. Marijuana can reduce the production of tears, leading to dry and irritated eyes.

When the eyes are dry, blood vessels may appear more prominent and redness can intensify.

This effect is commonly referred to as "cottonmouth," where users also experience a dry mouth.

Individual Sensitivity

People vary in their sensitivity to the red-eye effect of marijuana.

Some individuals may experience significant redness after consuming even small amounts of cannabis, while others may not notice a significant change in eye appearance.

The degree of redness can depend on factors like the strain of marijuana, the method of consumption, and individual physiology.

Strain-Specific Effects

Different strains of marijuana may have varying effects on eye redness.

Some strains may be more likely to cause red eyes due to their specific cannabinoid and terpene profiles.

For example, strains with higher THC content are generally more likely to lead to red eyes than those with lower THC levels.

Delivery Method

The method of consuming marijuana can influence the extent of eye redness. Smoking or vaping marijuana can lead to more pronounced red eyes compared to consuming edibles, tinctures, or topicals.

Inhalation methods allow THC to enter the bloodstream quickly, potentially resulting in a more immediate red-eye effect.

Temporary Effect

It's important to note that the redness of the eyes caused by marijuana is a temporary and benign side effect. It typically lasts for a few hours, and the redness gradually subsides as the effects of cannabis wear off.

There are no long-term health risks associated with red eyes from marijuana use.

To alleviate red eyes caused by marijuana use, individuals can try over-the-counter eye drops or artificial tears, which can provide relief from dryness and reduce redness. Staying hydrated by drinking water can also help combat dry eyes and cottonmouth.


In conclusion, the red-eye effect from marijuana use is primarily a result of vasodilation, lowered blood pressure, dryness, and individual sensitivity.

While it may be a noticeable side effect, it is generally harmless and temporary. If red eyes are a concern, using eye drops and staying hydrated can be effective in managing this effect while enjoying the other potential benefits of cannabis.

Please note that while Empire Rolling enjoys exploring topics like these, we are not medical professionals, and this post is not medical advice.