Sometimes a person's oesophagus, or throat, may swell up so much that the person can no longer breathe. This is called anaphylaxis. When this happens, a doctor must give the person a medicine called epinephrine to make the swelling go down. Some people with allergies to very common things, like bee stings or fish, carry this medicine with them so it can be used quickly in an emergency. The device they use to inject the medicine is called an epinephrine autoinjector. 