Gastroesophageal reflux (GER) is known to play a role in precipitating or worsening asthma attacks. Whether this effect is due to a bronchoconstricting vagal reflex, to aspiration of gastric material, or to both remains unclear. Treatment decisions are complicated by the difficulty of establishing a causal relationship between GER and asthma. However, compelling evidence indicates that severe, chronic, and treatment-resistant asthma is more likely to be associated with GER. Prolonged pH recording is warranted, and patients with clinical evidence of esophagitis should have an upper gastrointestinal tract endoscopy. Treatment for GER should be given if either investigation is positive. A beneficial effect of the anti-GER reflux treatment on the asthma symptoms confirms the link between the two conditions. Prokinetic agents such as cisapride should be used, and some patients also require an H2 histamine antagonist or a proton pump inhibitor. Vigorous anti-asthma treatment should also be given. Asthma is associated with an increase in intraabdominal pressure and with anatomic modifications of the cardia that increase the risk of GER. No data on the optimal duration of drug therapy for GER are available. It has been estimated, however that at least one year of therapy with anti-GER and bronchodilating agents is needed to stop the vicious circle linking asthma to GER and vice versa. If the symptoms worsen upon discontinuation of the medications, these should be given for a further year. Surgery should be considered in patients who require drug therapy for more than two to three years, especially if gastrointestindal symptoms are also present.