An EpiPen looks like a fat pen, but it is not for writing. Inside is a hidden needle and a strong medicine (epinephrine — the same idea as adrenaline). If someone is having a very bad allergic reaction — swelling, cannot breathe, the kind that can kill — they press it hard against the outer thigh, and the medicine goes in fast. You do not need to be a doctor; that is the whole point. People also keep one for a serious asthma attack that might kill them. Though actually, EpiPen began as a brand name, a marketing mix of epinephrine + pen. Like Kleenex for tissues, people now say “EpiPen” for that kind of emergency injector even when the box is another brand. Families who live with serious food allergies or insect stings often carry one. It is not everyday pain medicine, and it is not an insulin pen for diabetes.