Background and Objective: Traditional use of herbal medicinal plants in Saudi Arabia is common and in particular in Al-Baha region either in rural or urban areas for treatment of several ailments and no reports have been found about the mutagenicity of Saudi medicinal plants. Here we investigated the mutagenic/genotoxic effects of four herbal plants methanolic extracts namely, Acalypha fruticosa, Aloe vera, Jatropha spp and Ricinus communis, using the Ames test Methodology: For assessment of the mutagenicity of these four plants, we used the bacterial reverse mutagenicity assay (Ames test) without any metabolic activation system. The plants methanolic extract concentrations used were 0.1, 1.0 and 5.0 mg/ml. Results: Low concentrations of the extracts (0.1 mg/ml) of the four plants were found to be non-mutagenic (p < 0.05), while only the extracts of Aloe vera and Jatropha were found to be mutagenic in the second concentration (1.0 mg/ml). Meanwhile, Acalypha fruticosa extract at 1.0 mg/ml was found to be non-mutagenic and Ricinu communis was found to be cytotoxic at this concentration. At the concentration of 5.0 mg/ml the three extracts (Acalypha fruticosa, Aloe vera, Jatropha ) were mutagenic.  Conclusion:  Only higher concentrations, 1.0 and 5.0 mg/ml extracts of the herbal plants Acalypha fruticosa, Aloe vera and Jatropha, were found to be mutagenic/genotoxic in the reverse bacterial mutagenicity Ames test.