Abstract Although our understanding of asthma and its treatment has grown far beyond what was known during the 19th century, both the morbidity and mortality rate from asthma is much higher now than then. In the medical community this is known as the great asthma paradox. In this paper we present a system dynamics model to investigate the causes of this paradox. The model shows how the short-treatments that were not available in the past cause much of the problem behavior of asthma care today. We show the system mechanisms that cause short-term treatments to begat more treatments; that invite those with asthma to become addicted to short-term treatment; and that show how side effects of short-term treatments deteriorate asthma conditions. We then introduce the long-term treatment concepts into the model and examine their impact on asthma care. Through model simulations we show how a proper combination of the long-term and short-term treatments can create optimal results. The results from our model are compatible with clinical results observed by physicians experienced in the care of people with asthma.