Red bloodshot eyes after waking up in the morning is a sign of conjunctival congestion, which is usually caused by the following reasons: first, it is due to the fact that the eyelids are not completely closed when sleeping, revealing a gap, resulting in part of the conjunctival tissue being exposed to the air for a long time, which causes mild damage to the conjunctiva after the evaporation of tears; second, it is due to the allergic reaction caused by the eyes coming into contact with the cotton wool, dander and mites of pillowcases, sheets and other bedding when sleeping. The second is caused by the allergic reaction caused by the mites, in the eyes, congestion, at the same time, will be accompanied by eye itching, through the diligent change of bedding can be eliminated; third, is caused by conjunctivitis, such as pillowcases for a long time without cleaning, replacement, will lead to a large number of bacteria on the surface, sleep when the eyes contact the pillowcase, it is possible to trigger bacterial infection, resulting in the formation of conjunctivitis.