Hypokalemia is a common side effect in adult asthmatic patients on beta 2 adrenergic therapy. There is limited information in regard to hypokalemia and its relation to the clinical responses following administration of beta 2 agonist therapy in children with asthma. We observed that salbutamol inhalation significantly improved asthmatic symptoms as demonstrated by increases in peak expiratory flow (PEF: 122.37 +/- 75.38 vs. 152.59 +/- 80.29; P< 0.001) and venous oxygen tension (Pv,O-2: 33.24 +/- 4.95 vs. 58.16 +/- 2.31; P < 0.001), and decreases in respiratory rate (RR: 36.39 +/- 3.78 vs. 28.62 +/- 3.12; P< 0.01), clinical scores (CS: 3.59 +/- 1.28 vs. 1.59 +/- 0.71), and venous PCO2 tensions (PV,CO2: 40.84 +/- 2.67 vs. 34.75 +/- 2.31; P < 0.001). Salbutamol-induced hypokalemia was correlated with a decrease in RR, and an increase of Pv,O-2 and PEF. These findings suggest that the same mechanism is involved in eliciting hypokalemia and bronchodilatation. Pediatr Pulmonol, 1999; 27:27-31, (C) 1999 Wiley-Liss, Inc.