Material and method: The 28 cleft lip and cleft palate patients (19 females, 9 males), 15–31 years of age who had been undergoing treatment with fixed orthodontic appliance at Dental Hospital, Faculty of Dentistry, Prince of Songkla University were divided into two groups. By randomized sampling, the 13 subjects in study group were received 10g/50ml/day of probiotic powdered milk containing Lactobacillus paracasei SD1 while the 15 subjects in control group were received 10g/50ml/day of control milk. Both groups were advised to intake the received milk at breakfast time for 30 days. Salivary mutans streptococci counts, plaque index and salivary pH were performed pre-milk consumption as T0, immediately after post-milk consumption as T1 and 1 week interval for 4 weeks post-milk consumption as T2, T3, T4, T5.