The conjunctiva is a soft, smooth and transparent film located on the inner surface of the eyelid and the surface of the eye, which has certain defensive capabilities, but when the defensive capabilities are weakened or when external pathogenic factors increase, it causes inflammation of the conjunctival tissue, which is collectively called conjunctivitis. Conjunctivitis can be classified as hyperacute, acute, subacute, or chronic according to the course of the disease. Acute conjunctivitis is commonly known as “pink eye” and is somewhat contagious. The causes can be broadly divided into exogenous and endogenous, as follows: 1. Exogenous acute conjunctivitis: Since most of the conjunctiva is in direct contact with the outside world, it is susceptible to the stimulation of infectious (such as bacteria, viruses, and chlamydia, mycobacteria, allergic reactions, etc.) and non-infectious factors (trauma, chemicals and physical factors, etc.) in the surrounding environment, and the conjunctiva is rich in blood vessels and lymphatic tissues, and its own and external antigens can easily sensitize it. The antigens of the conjunctiva can easily sensitize it. 2. Endogenous acute conjunctivitis: the causative organism infects the conjunctiva through blood or lymph, or has an allergic reaction to infectious agents elsewhere in the body. Inflammation can also come from the direct spread of neighboring tissues. Therefore, there are various causes of acute conjunctivitis.