A method for improving the toughness of a CBN product made by a high temperature/high pressure (HP/HT) process commences by forming a blend of an oxygen getter and CBN product-forming feedstock. The blend is subjected to a CBN high temperature/high pressure (HP/HT) process for forming a CBN product. The amount of oxygen getter in the blend is sufficient to improve the toughness of the CBN product. The resulting CBN product desirably has an oxygen content of less than about 300 ppm. Oxygen getters include Al, Si, and Ti. The HP/HT process is conducted in the absence or presence of catalytic materials.