Adrenalin, also known as epinephrine, is a hormone produced by the adrenal glands in response to stress or danger. It plays a crucial role in the body's "fight or flight" response, preparing the body to react quickly in emergencies. When released, adrenalin increases heart rate, elevates blood pressure, and boosts energy supplies. This hormone also helps improve blood flow to muscles and enhances the brain's ability to think clearly under pressure. Adrenalin is often used in medical settings, such as treating severe allergic reactions or cardiac arrest, highlighting its importance in both natural and clinical scenarios.