The human cough reflex is a vital protective and defensive reflex, and its integrity is important to protect the organism from irreparable harm.1It is therefore disappointing that our knowledge of the reflex, particularly the central control mechanisms, is scanty and that what little knowledge we do have is largely extrapolated from animal studies. This may explain the lack of effective antitussive agents in patients with a persistent cough. The only effective cough suppressant under these circumstances is morphine and it needs to be given in sedative doses, which has little clinical utility. A possible explanation for the difficulty in suppressing cough in humans is that the reflex is robust and highly conserved to protect the organism. There are circumstances in which the cough reflex is so sensitive that it interferes with quality of life, has adverse health effects, and needs to be suppressed. Many of these circumstances are associated with underlying conditions such as asthma, gastroesophageal reflux, and rhinitis, and in a small proportion there is no identifiable association.2An understanding of the pathophysiology of the coordination of the reflex in the medulla will fast track the development of effective antitussive agents. The cough reflex is also subject to voluntary control, and this raises the possibility of psychogenic influences. There may be constitutive factors that determine the sensitivity of our cough reflex, similar to bronchial hyperresponsiveness, although this has not been adequately addressed because of the varying methodology for cough challenge studies. It has been suggested that the cough reflex is more sensitive in women, but at least one study3 found no difference between men and women.