Aim: The aim of the study was to test the antibacterial activity of manuka honey and compare its efficacy with another com- mercially available honey (Dabur honey) on the cariogenic bacteria on Streptococcus mutans and Lactobacillus.

Materials and methods: An in vitro study was carried out on 40 agar specimens; the samples were divided into two groups of 20 samples consisting of S. mutans and Lactobacil­ lus respectively. The 20 samples in each group were further subdivided into four groups of five each, which were tested with 25% manuka honey, 100% manuka honey, 25% Dabur honey, and 100% Dabur honey for both Lactobacillus and S. mutans groups. The antibacterial activity was tested using the agar well diffusion method against S. mutans and Lacto­ bacillus. Antibacterial activity was assessed by measuring the diameter of inhibition of zones surrounding the wells. The results obtained were statistically analyzed (one-way analysis of variance test, p-value).

Results: The results showed that 25% of manuka honey has statistically significant (p ≤ 0.001) antibacterial effect than 25% of Dabur honey on both Streptococcus and Lactobacillus species, and manuka honey with 100% concentration showed a statistically significant (p ≤ 0.001) antibacterial effect than 100% Dabur honey on the same species of bacteria. 100% of both the honeys showed statistically significant (p ≤ 0.001)antibacterial effect than 25% concentrations of the same on S. mutans and Lactobacillus.

Conclusion: Manuka honey had more antibacterial activity than Dabur honey on S. mutans and Lactobacillus bacteria in the in vitro study. This effect was dependent on the concentra- tion of honey used.