In clinical practice, gastrooesophageal reflux (GER) and bronchial asthma often coincide. In the case of sufficient asthma control, the asthma does not need to be taken into account when treatment of GER is being evaluated. In patients with symptomatic asthma despite adequate antiasthmatic treatment, a possible causal relationship between GER and the poor responsiveness to asthma therapy has to be considered. An algorithm to guide the diagnostic and therapeutic steps in such cases is presented.