the one pill people take to stop allergies and asthma, it prevents it rather than treats it ## Not sure if this is the one you're thinking of but Uniphyl (Theophylline) might be the pill you are looking for. Excerpt from the Mayo Clinic: You take this bronchodilator in pill form every day. It's especially helpful for relieving your nighttime symptoms of asthma. But theophylline may cause side effects, such as nausea and vomiting, severe abdominal pain, diarrhea, acid reflux, confusion, fast or irregular heartbeat, and nervousness. If you're taking theophylline, get regular blood tests to make sure you're getting the correct dosage.