Objective To study the inhibitory effect of erythritol by contrast to xylitol on growth and acid production of Streptococcus mutans（S.mutans）. Methods S.mutans were incubated respectively in 0.5%, 1%, 2%, 4%, 8%, 12%, 16% erythritol or xylitol culture medium under anaerobic conditions. The A and pH value of the mediums were measured at 0, 2, 4, 6, 8, 10, 12, 18, 24 hours, following the profile plots by SPSS. Results The data of A were higher in 0.5%, 1%, 2% erythritol culture medium than in xylitol culture medium at the same concentration, while lower in 8%, 12%, 16% erythritol culture medium than in xylitol culture medium at the same concentration. The data of pH were lower in 0.5% , 1% , 2% erythritol culture medium than in xylitol culture medium at the same concentration, while higer in 8%, 12%, 16% erythritol culture medium than in xylitol culture medium at the same concentration. It indicated that the growth and acid production of S.mutans were higer in 0.5%, 1%, 2% erythritol culture medium than in xylitol culture medium at the same concentration, while lower in 8%, 12%, 16% erythritol culture medium than in xylitol culture medium at the same concentration. Conclusion Compared with xylitol, erythritol in low concentration has weaker effort on the growth and acid production of S.mutans, while having stronger effort in high concentration.
