The effects of the antihypertensive drug captopril on salivary secretion rate and composition was evaluated in 24 healthy adults (18-46 yr) according to a double-blind, cross-over design. Unstimulated and paraffin-chewing stimulated whole saliva and 3% citric acid stimulated parotid and submandibular-sublingual (SM-SL) secretion were collected at 10.30 a.m. (about 2h after intake of breakfast) on day 0 (baseline values), day 1 (experimental acute values) and day 7 (experimental chronic values) in each treatment period. In 8 of the subjects, also morning samples were collected at 7.30 a.m., with the test subjects in a fasting condition. Whole saliva was assessed for flow rate and for concentrations of sodium, potassium, chloride, calcium and phosphate. In addition, parotid and SM-SL secretion were assessed for concentrations of total protein, hexosamine, sialic acid, lactoferrin and salivary IgA and for activities of amylase, lysozyme and salivary peroxidase. During treatment with the angiotensin converting enzyme inhibitor captopril, the secretion rates tended to increase for unstimulated and paraffin-chewing stimulated whole saliva and for parotid secretion. For salivary composition, no alterations were observed in any of the collected secretions.