Inhaled therapy using a metered-dose inhaler (MDI) with attached spacer has been increasingly recognized as the optimal method for delivering asthma medication for acute attacks and chronic prophylaxis. However, in developing countries the cost and availability of commercially produced spacers limit the use of MDI-spacer delivery systems. A 500-ml plastic bottle has been recently adapted to function as a spacer. This article reviews the current data on the efficacy of this bottle-spacer and discusses its advantages and limitations. It is concluded that a modified 500-ml plastic bottle is an effective spacer; modification and use of this device should be incorporated into international guidelines for the management of children with asthma.