Background: There is currently much interest in the role of probiotics in the modulation of colonic microflora to improve host health (Parvez, 2006) The probiotic strain Bifidobacterium animalis (B. animalis) DN-173010 contained in a leading brand probiotic yogurt, claims to exert health benefits with the daily consumption of this product over 2 weeks. The aims of this study are to confirm results of previous studies showing consumption of B. animalis reduces oro-caecal transit time (OCTT) (Agrawal et al., 2008). Secondly to determine whether any change in OCTT occurs during the 3 week consumption of yogurt containing B. animalis. Methods: This study was a randomised, controlled, unblinded parallel trial. Participants were recruited via e-mail using convenience sampling. Participants (n = 9) consumed either Activia containing B. animalis (n = 5) or a non-probiotic yogurt (n = 4) for 3 weeks. OCTT was measured using a hydrogen breath analyser. Fibre intake, gastrointestinal habits such as stool type and frequency were collected through participant self reporting. Data was analysed using a Mann–Whitney U-test and Paired T-test, possible correlations were investigated using a Spearmans rho test. Results: The control group had a higher mean OCTT (127.5 min) compared with the probiotic group with a mean OCTT of (97.0 min) however this was not a significant difference (P = 0.381) The control group on average had a higher fibre intake (181 ± 92 g per week) compared with the probiotic group consuming (148.6 ± 32 g per week) however this difference was not significant (P = 1.000). No correlations were found between OCTT and fibre intake (P = 0.370) or stool type (P = 0.310) and frequency (P = 0.780). No significant change in symptoms between the groups was observed. Discussion: The findings suggest consumption of B. animalis within this brand of yoghurt had no significant impact on OCTT therefore this study did not confirm findings from other studies. Nonetheless the impact of any probiotic strain on OCTT is still unknown as the microbiota within the caecum is different compared to the colon where the majority of probiotic research is conducted. This study cannot comment into the impact of B. animalis on other transit time parameters. Conclusion: These findings suggest the consumption of B. animalis had no impact on OCTT or any other GI parameter. This study was conducted using a small sample however much of the evidence conducted investigating OCTT used a small sample size, therefore more evidence is required. References: Agrawal, A., et al. (2008) Clinical trial: the effects of a fermented milk product containing Bifidobacterium lactis DN-173 010 on abdominal distension and gastrointestinal transit in irritable bowel syndrome with Constipation. Aliment. Pharmacol. Ther. 29, 104–114. Parvez, S., Malik, K.A., Ah Kang, S. & Kim, H.-Y. (2006) Probiotics and their fermented food products are beneficial for health. J. Appl. Microbiol. 100, 1171–1185.