This study entitled the effect of Chinese Hibiscus (Hibiscus rosa-sinensis) Extract on the number of revertant Colonies of Samonella typhimurium TA 98 and TA 100 Against Mitomcyin C using Modified Ames Salmonella Mutagenecity Test: A pilot study, aims to identify the capability of the Hibiscus flower in preventing the reversion of mutant colonies Salmonella typhimurium TA 98 and TA 100. With the use of modified Ames Salmonella Assay, using three trials with two organisms per trial, the number of revertant colonies were determined. Each trial consisted of seven variables having three plates each variable. The seven variables involved were: Water, Mitomycin-C, Water with mitomycin-C, 50% Hibiscus Extract, 100% Hibiscus extract, 50% Hibiscus extract with mitomycin-C, and 100% Hibiscus Extract with mitomycin-C. After culvitation, the plates were sent to a medical technologist for the colony count. The results showed that at least one mean was significally different than the other means. Upon assesing the means of the different variables it was discovered that the highest mean was attained by the positive control which was mytomycin C, and the lowest mean was attained by mitomycin-C with 50% Hibiscus extract. Based on the results, both 100% and 50% Hibiscus rosa-siensis extract has the capacity to prevent the reversion of mutant colonies in the presence of a mutage, which is Mitomycin-C. furthermore, fifthy percent extract was proven to be more effective in inhibiting the growth of revertant colonies than the 100% concentration.