Large-volume parenteral solutions were submitted to heat treatments after being inoculated with Bacillus stearothermophilus ATCC 7953 (T-r = 121 degreesC) and Bacillus subtilis ATCC 9372 (T-r = 104.5 degreesC) spores. The average decimal reduction time for B. stearothermophilus ranged from a D-121degreesC value of 1.31 to 3.14 min, in glucophysiologic and Ringer's solutions respectively. For B. subtilis, D-104.5degreesC value increased from 0.69 to 1.37 min, in Ringer's (pH=5.91) and 50% glucose (pH 3.05) solutions respectively. The z value ranged from 7.95 degreesC (20% mannitol solution) to 13.14 degreesC (50% glucose solution), corresponding to an activation energy (Ea) of 81.48 and 49.30 kcal/mol, respectively.