Anti oralmicrobial effects of Nulembo nucifera were determined against S.mutans, S.sobrinus S.sobrinus, F.nucleatum, and A.actinomycetemcomitans using paper disc method, minimum inhibitory concentrate (MICs). Extracts of lotus leaf showed the highest yield. MeOH extract is 21%, Chloroform fraction is 4.2%, ethylacetate fraction is 8.2%, water fraction is 19%. Different parts such as flower, leaf, seed and pod showed antimicrobial effects against S.mutans, with flower and seed extracts showing strong antimicrobial effect aganinst S.sobrinus KCCM11897. Leaf extract(1000pm concentration) showed over 50% inhibitory effect against S.mutans and S.sobrinus KCCM11897. Flower extract showed over 40% inhibitory effect against F.nucleatum and A.actinomycetemcomitans. MICs of flower extract against S.sobrinus KCCM11897,11898 and leaf extract against S.mutans, S.sobrinus KCCM11897 were $625;{mu}g/ml$, indicating Nulembo nucifera extract can exert antimicrobial activity even at low concentration. All extractes with heat at $120^{circ}C$ had antimicrobial activity, which means that is a very stable substances. F.nucleatum and A.actinomycetemcomitans was stable against acid it had a trend that the more akali side was the lower acitivity.