Hypogeusia is a reported side effect of captopril. Linkage of hypogeusia to zinc deficiency has been suggested. We objectively assessed taste acuity using Henkin's three-drop stimulus technique and measured plasma zinc (PZn) level and urinary zinc excretion in 31 hypertensive patients. Of these, 11 were long-term, high-dose captopril recipients (more than 6 months, 266 +/- 34 mg/day), six were short-term captopril recipients (less than 6 months, 104 +/- 40 mg/daily dose), and the remaining 14 served as noncaptopril controls. Compared to controls, the long-term captopril group had significantly higher taste detection and recognition thresholds, lower PZn (91 +/- 3 vs. 100 +/- 3 micrograms/dl, P less than 0.05) and higher urinary zinc excretion (1017 +/- 89 vs. 609 +/- 76 micrograms/day, P less than 0.005). The short-term captopril group did not differ significantly from the noncaptopril group except for higher taste-recognition thresholds for NaCl and sucrose (P less than 0.05). Discontinuing captopril improved taste acuity and almost normalized zinc parameters in two patients on long-term captopril. These results suggest that abnormalities of taste are commonly associated with captopril therapy and may be related to changes in zinc metabolism. This is especially true in patients on long-term, high-dose captopril therapy.