When the expected effect of an inhaled drug is not achieved, the cause could be poor inhalation technique and consequently a low pulmonary dose. A simple in vivo test to evaluate the pulmonary dose would be a benefit. This study evaluates the relative and systemic bioavailability following inhalation of nebulized sodium cromoglycate (SCG) in healthy subjects. Blood samples were collected during 240 min and urine was collected in two portions, up to 6 h post-inhalation. Two exposures were performed and comparisons based on the quantification of drug in plasma and urine by a high-performance liquid chromatography (HPLC) procedure were done. In one of the exposures, a pulmonary function test was performed to study if an expected effect of increased absorption could be detected. There was a good correlation between the two exposures shown in the plasma concentrations, but not in the urine analyses. The forced exhaled volume manoeuvres were associated with a higher Cmax and plasma concentrations up to 60 min post-inhalation (P<0.01). This effect was not detected in the urine analyses. We conclude that this pharmacokinetic method with inhaled SCG and plasma analyses could be used to evaluate individual inhalation technique. The HPLC method used was rapid and had adequate sensitivity.