Many patients fail to use metered dose inhalers (MDI) correctly even after receiving tuition, as the technique requires hand-lung coordination, and breath-holding. The article describes the various Auxiliary Delivery Systems designed to circumvent the problem, compares them with MDI, and reports a new "Aerosol-in-Bag" method which is home-made, easy for the patient to assemble, and hardly adds to the cost of the MDI. It could be particularly useful in third-world countries where cost and availability are serious considerations. The new method was found to be as effective as a correctly used MDI, in spite of its extreme case of use, as it requires no coordination or special breathing techniques.