People with bloodshot eyes will appear red in the eyes because of the dilated blood vessels in the surface of eyes. And there are many factors that can contribute to it. One of the most common reason for red eyes is allergy from environmental factors such as pollen, dust, blowing wind and sun exposure etc. Besides, pink eyes and glaucoma can also be the factors of bloodshot eyes. So, if you want to cure it, you shall know the causes of bloodshot eyes first.
Usually, bloodshot eyes are caused by a lack of sleep. A lack of sleep is not a kind of disease. However, if you keep this bad habit for a long time, it may turn into a kind of eye disease. Moreover, bloodshot eyes is also the result of some kind of medication results. Of course it is not a good result. Only side effects can cause that, lol. If you want to know worse reasons, well, maybe pink eye. You know, the most obvious symptom of an pink eye is red eye.