Prophylactic/ˌprəʊfəˈlæktɪk/ Definition 1 of 4Pro Tip 1/3Disease Prevention Used when aiming to stop diseases before they start, particularly in medicine. Doctors recommend prophylactic vitamins during flu season. Pro Tip 2/3Not a Cure It's for preventing disease, not treating it once you have symptoms. Taking prophylactic measures now can save you trouble later. Pro Tip 3/3Beyond Medicine Can refer to any action taken in anticipation to prevent harm. Applying sunscreen is a prophylactic approach against sunburn.