2-methyl-3(3'-methyl-2'-pyridyl)-4 (3H) quinazolinone (SRC-820) and methaqualone inhibited the growth of Streptococcus faecalis-R (ATCC-8043). Phosphoenolpyruvate formation from 3-phosphoglycerate by an enzyme extract of S. faecalis was inhibited by SRC-820. With edetate or fluoride, an additive inhibitory effect by SRC-820 was observed.