If you have an allergy to cold medicine, you need to stop taking cold medicine and use anti-allergy medication to treat it. If the allergy is not very serious, you can use loratadine, paracetamol or cetirizine hydrochloride to treat it. If the symptoms are not very severe in children, dexloratadine can also be used to relieve the allergy. If more serious allergies occur, it is necessary to go to the hospital immediately to get intravenous glucocorticoids to relieve the allergy, otherwise it is very dangerous and may lead to anaphylactic shock or laryngeal edema, which can cause severe respiratory obstruction. Therefore, if a more serious allergy occurs, you must go to the hospital in a timely manner and avoid taking this cold medicine in the future, otherwise it is very dangerous. When you have a cold, it is best to simply use Chinese medicines for treatment, for example, you can try using Banlangen granules, which have fewer side effects.