The objectives of this study were to determine the risk for coughing as an adverse reaction to angiotensin converting enzyme (ACE) inhibitors under everyday circumstances in a large population and to study whether this adverse effect is more common in women. A population-based case-control study was used. The study was set in the practices of 161 Dutch general practitioners (GPs), in which all consultations, morbidity, mortality, medical interventions and prescriptions were registered during 4 consecutive 3-month periods in 4 consecutive groups of 40-41 GPs. The subjects were 2436 patients with incident coughing and up to 3 controls per case were obtained (total group: 7348 controls), matched for GP and a contemporary consultation in the same 3 months. All cases and controls were 20 years or older and had no notification of respiratory infections, influenza, tuberculosis, asthma, chronic bronchitis, emphysema, congestive heart failure, sinusitis, laryngitis, haemoptysis or respiratory neoplasms during the 3-month period. The results showed that cases were 3.6 times as likely as controls to have been exposed to ACE inhibitors (95% CI: 2.4-5.5) but after adjustment for potential confounders the odds ratio was 2.5 (95% CI: 1.6-3.9). The crude odds ratio for males was 2.7 (95% CI: 1.4-5.1) and for females 4.2 (95% CI: 2.4-7.5). The adjusted odds ratio for males was 1.8 (95% CI: 0.9-3.5) and for females 2.7 (95% CI: 1.5-4.8).(ABSTRACT TRUNCATED AT 250 WORDS)