The sodium bicarbonate (NaHCO3) dosage used in treating the patients with organophosphorous pesticide (OP) poisoning did not result in sufficient alkalinization of the blood. We thus investigated the effects of higher doses by infusion (5 mEq/kg over 1 hour, followed by 5-6 mEq/kg daily until recovery or death) to maintain the arterial pH between 7.45 and 7.55. There were 26 (14 M and 12 F) patients aged 24.1 +/- 9.7 years and 27 (16 M and 11 F) aged 25.7 +/- 9.1 years in the test and contro groups, respectively. Arterial blood pH of the test group (7.48 +/- 0.02) was much higher (p < 0.0001) than the controls (7.36 +/- 0.02). The total atropine doses used for the control patients (129.45 +/- 61 mg) was significantly (p = 0.048) higher than the controls (93.4 +/- 59.1 mg). Hospitalization days were statistically higher (p = 0.037) in the controls (5.59 +/- 1.97 days) than in the bicarbonate group (4.33 +/- 1.99 days). Infusion of high doses of NaHCO3 appears to be beneficial in treatment of patients with OP poisoning.