Conjunctivitis, commonly known as pink eye, is an inflammation or infection of the transparent membrane (conjunctiva) that covers the white part of the eye. There are several types of conjunctivitis including viral, bacterial, allergic, toxic, and periorbital cellulitis. Symptoms include redness, tearing, irritation, discharge, and swelling. Treatment depends on the underlying cause but may include antibiotic eye drops, antiviral medication, or antihistamine eye drops. Good hygiene practices can help prevent the spread of contagious forms of conjunctivitis.