All 254 children in the randomized, double-blinded study used low dose controller inhalers -- "two puffs twice daily" -- for a standard maintenance dose of inhaled steroid medication. When parents noticed their child had yellow zone symptoms, the researchers instructed them to use a different inhaler for seven days. Half of the inhalers were the same low dose, and the other half contained five times the maintenance dose. Across 395 yellow zone episodes, the researchers did not find any significant difference in the number of asthma attacks that ultimately required systemic steroids. Despite a 16% increase in exposure to inhaled steroids, children in the high-dose group did not experience fewer attacks.