If you or someone you love has a severe allergy to insect bites, certain foods or other allergens, the Epi-pen can be a life-saver. The Epi-pen contains an injection of the adrenal hormone epinephrine, a stimulant that can counter the symptoms of a severe allergic reaction, including: swelling of the face, constriction of the airways, a swollen tongue or throat, trouble breathing, a severe drop in blood pressure, a weak and rapid pulse, hives, and nausea, vomiting or diarrhea.Here's how to use an Epi-pen. First, BEFORE you are in a crisis situation, take the time to read all directions on the label...you will not have much time to do this "in the moment."When you need to use the Epi-pen:1. Pull off the blue safety release cap. 2. Swing the orange tip very firmly against the outer thigh so it 'clicks.' HOLD on thigh for approximately 10 seconds to deliver the drug. Do NOT inject into the buttocks; this may not be effective. 3. After the injection, don't worry if there is excess liquid in the device. There's usually a small amount that can't be used. Now, if the allergic reaction was caused by an insect sting, you should remove the stinger. Grab it with a pair of tweezers or your fingers but don't squeeze or push the stinger. 4. Proceed to the nearest hospital emergency room RIGHT AWAY. The effects of epinephrine may wear off and the allergic reaction may reappear. You need medical support to be sure you are safely through the episode.Keep in mind, the injection can cause upset stomach, vomiting, sweating, dizziness, shakes, nervousness, pale skin and headaches. To learn about more allergies and how to treat them, check out other videos in this series.