Why does smoking marijuana make your eyes red?

Answer 1

Marijuana decreases pressure in the eyes and increases blood flow. When this happens, the arteries in the eye-ball expand (due to decreased pressure). These areteries, especially when expanded, are visible in the white portion of the eye and make the eye appear "bloodshot" or red.

This very result (decrease of pressure in the eye) is the primary reason marijuana is used to treat glaucoma. Glaucoma is the condition where there is excessive pressure in the eye. In some patients, the pressure can become so severe that it causes damage to the retinal nerve, ultimately damaging the patient's vision. Marijuana decreases this pressure.

Answer 2

It is called vasodilatation. It is an effect of alcohol. Trust me, I know. It causes the blood vessels everywhere in your body to expand. That is why you get bloodshot eyes and feel warm after a few beers.

Don't drink in the winter to keep warm. Vasodilatation actually causes you too lose more heat than you gain. You just feel hot from all of the blood the surface of the skin. You could actually slip into hypothermia.

Answer 3

Because tHc makes the internal pressure in the eye decrease and increases blood flow so the blood vessels in your eye expand and appear red.

Answer 4

Marijuana (THC) causes an increase in blood pressure and heart rate. High blood pressure causes red eyes.