Apple cider vinegar is a kind of magic beverage. It is full of vitamin and tartaric acid, which can restrain tired, improve one's beauty, prevent colds, etc. For pink eyes, if you insist on drinking it, then it well help you in a certain degree, but it does not improve your situation directly. It acts as assistance. If you really want to get rid of pink eyes, you need to keep your eyes clean all the time. Leave no environment for bacterium to live. Physiological saline would be helpful. In a long run, drinking apple cider vinegar every day can enhance your immune system. You won't be that easy to get pink eyes.