en Animal Models Animal Models Original article Original article <strong>Introduction</strong>: <em>Dracocephalum polychaetum</em> Bornm and <em>Nepeta cataria</em> L. are two plants from the Lamiaceae family with antibacterial, antifungal, and antiviral properties. This study evaluated the phenolic compounds, antioxidant activity, and effect of aqueous extracts on the survival of <em>Lactobacillus</em> <em>acidophilus</em> and <em>Bifidobacterium</em> <em>animalis</em> in a simulated gastrointestinal environment. <strong>Method</strong>: The aerial parts of plants were collected at the vegetative growth stage from the Hanza-Kuh&#39;s highlands in the Bahr Asman region of Jiroft city, Iran, in spring 2018. The total phenolic content of plants and antioxidant activity were measured using Folin&ndash;Ciocalteau and DPPH (2<em>,</em> 2<em>-</em>diphenyl<em>-</em>1<em>-</em>picrylhydrazyl) methods, respectively. For investigating the survival of probiotic bacteria in a simulated gastrointestinal environment, bacterial suspension was inserted into tubes containing 0, 100, 250, 500, and 1000 ppm of extracts and then incubated in a simulated gastrointestinal environment. The probiotic bacteria were counted using an MRS agar medium at various incubation times. <strong>Results</strong>: The results showed that the amount of total phenolic compounds in the <em>D. polychaetum</em> Bornm extract (44.55 mg/g dry matter) was higher than that of<em> N. cataria</em> L. (18.37 mg/g dry matter). With increased extracts concentrations, the percentage of DPPH-free radicals increased, and <em>D. polychaetum</em> Bornm extract in all concentrations showed higher DPPH free radical inhibitory content compared to the <em>N. cataria</em> L. extract. The viability results in the same gastrointestinal environment showed that samples containing <em>N. cataria</em> extract had a more remarkable survival rate than the controls and <em>D. polychaetum</em> Bornm extract. <strong>Conclusion</strong>: Using less than 500 ppm of <em>D. polychaetum</em> Bornm and <em>N. cataria</em> L. aqueous extracts can increase probiotic bacteria growth and viability. Dracocephalum polychaetum Bornm, Nepeta cataria L., antioxidant activity, Probiotic bacteria 5 11 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-288-1&slc_lang=en&sid=1 Fatemeh Shahdadi fatemeh.shahdadi@gmail.com 0000-0002-7523-3429 No Department of Food Science and Technology, Faculty of Agriculture, University of Jiroft, Jiroft, Iran Maryam Payandeh payandeh82@gmail.com 0000-0003-2199-7180 No Department of Biology, Faculty of Science, University of Jiroft, Jiroft, Iran Ali Salehi Sardoei alisalehisardoei@gau.ac.ir 0000-0002-4054-3750 Yes Ph. D. student in Horticulture Sciences Biotechnology, Faculty of Plant Production, Gorgan University of Agriculture and Natural Resources