Corticosteroids Not all steroids are the bad, muscle-building kind that some athletes take illegally. Corticosteroids are an important kind of controller asthma medication. Controller medications keep the airways in the lungs open and clear so you can breathe. Back to Articles Related Articles Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.