Bloodshot eyes occur when the small blood vessels on the surface of the eye become inflamed and congested with blood. This is usually in response to an insufficient supply of oxygen in the cornea or tissues covering the eyes. They are usually a consequence of eyestrain, fatigue, and improper diet. Consumption of alcohol can worsen bloodshot eyes.
A deficiency in vitamin B2 can also cause bloodshot eyes. If this is the cause, once the body receives the nutrients it needs, the congestion in the blood vessels should disappear.
Vitamin B2, also called riboflavin alleviates eye fatigue and is important in the prevention and treatment of cataracts. High levels of vitamin B2 are found in cheese, egg yolks, fish, legumes, meat and poultry. Herbs that contain vitamin B include alfalfa, burdock root, and chamomile.