his study was carried out in order to determine the toxic and mutagenic and antimutagenic effects for Mallow (Malva parviflora) against the mutagenic effect of Methotrexate (MTX).The effect was studied in a bacterial system (G-system). The used system consisted of three isolates G3 Bacillus spp, G12 Arthrobacter spp and G27 Brevibacterium spp. The study depended on recording survival fraction (Sx) as an indicator for the induction of Streptomycin and Refampicin resistance mutants as a genetic

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... rker. Water Extract was prepared from fresh and dry mallow leaves, stems, flowers and roots Gradual concentrations of plant water extracts were use to choose the suitable concentration which is remembered the negative control. The interactions included three types of treatments (pre - MTX, with- MTX and post-MTX) as a chemical mutagen in order to determine the mechanisms of this plant extracts in preventing or reducing the genotoxic effect of MTX. The results showed that the interaction effect between the optimum concentration of water extract and the mutagen on survival fraction (Sx) increase the value of the survival fraction of G-system isolates to reach normal value compare with positive control (MTX ). The results of the interaction between optimum concentration for extracts and the treatment with mutagen to induce resistance mutant for streptomycin and refampicin found that the MTX had no effect to induce resistance mutant for these two antibiotics, for the three types of treatment (pre-MTX, with-MTX, and post- MTX) for all extracts, the water extract suppress or repair mutant and give protection 100% for bacterial cells.