To evaluate the malodor level and to explore the effect of mechanical self-cleaning of tongue coating in patients with halitosis originating from tongue coating.Ten patients with halitosis originating from tongue coating were enrolled and divided into two groups randomly. The patients in test group received instruction of mechanical cleaning of tongue coating while no such instruction was given to control group. Organoleptic test (OLT) score, volatile sulfide compounds (VSC) value, area of tongue coating (Ta), thickness of tongue coating (Tt) and periodontal condition were recorded at baseline and were repeated at the end of 1 week, 2 weeks, 4 weeks and 8 weeks later. The clinical outcomes were compared at different time points between the groups. Also, changes within the group were analyzed.As time went by, tongue coating area and thickness tended to decrease in test group while the changes showed no statistically difference (P>0.05). The organoleptic score in test group decreased significantly (P0.05), though they showed a tendency to decrease and fewer changes in control group were found. Compared with the baseline, average probing depth and bleeding index (P0.05). Plaque index showed no difference at different time points in both the groups (P>0.05).Mechanical self-cleaning of tongue coating did not influence plaque index while it had tendency to reduce tongue coating area and thickness. Malodor could be released after self-cleaning of tongue coating to a certain extent, indicating necessity and importance of intervention role by dentists.