Abstract. Objective: To determine whether intravenous (IV) hypertonic sodium bicarbonate is effective in the reversal of QRS widening associated with severe Taxus intoxication. Methods: Seventeen anesthetized and instrumented swine were poisoned with an IV extract of Taxus media until doubling of the QRS interval on electrocardiography was achieved. After poisoning (time zero), the animals received either 4 mL/kg IV 8.4% sodium bicarbonate (experimental group; 6 animals), a similar volume of 0.7% NaCl in 10% mannitol (mannitol group; 6 animals), or nothing (control group; 5 animals). The main outcome parameter was QRS duration. Secondary outcome parameters were mean arterial pressure (MAP), heart rate (HR), and cardiac index (CI = cardiac output/kg). Additionally, arterial pH, partial pressure of carbon dioxide (pCO 2 ), and plasma-ionized calcium, sodium, and potassium were monitored. Results: Taxus toxicity, defined as a 100% increase in QRS duration, was produced in all animals. The an-