Tetryzolin
The active ingredient, tetryzolin, is a so-called sympathomimetic, which, as the name suggests, imitates the action of the sympathetic nervous system. Tetryzolin binds to certain sympathetic receptors, which leads to a narrowing of the vessels in the eye. This leads to reduced blood circulation, less redness and a decrease in the flow of tears. The eye swells and the symptoms of conjunctivitis are relieved.