10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 1 2015 (January - March) The present work was undertaken to evaluate the polyphenolic content, antioxidant and antiviral properties of two wild medicinal plants; lessThan i greaterThan Achillea fragrantissima and Nitraria retusa lessThan /i greaterThan . The crude extracts of both plants were prepared using methanol and ethyl acetate solvents. Generally, total phenolic content ranged from 0.31 to 15.05 mg gallic acid equivalents /g dw, where total flavonoid content varied from 0.23 to 9.30 mg quercetin equivalents /g dw. Methanolic extract of lessThan i greaterThan A. fragrantissima lessThan /i greaterThan showed the highest phenolic and flavonoid content compared to lessThan i greaterThan N. retusa lessThan /i greaterThan . However, methanolic extract of  lessThan i greaterThan N. retusa lessThan /i greaterThan showed strong antioxidant activity (IC lessThan sub greaterThan 50 lessThan /sub greaterThan = 68 µg ml lessThan sup greaterThan -1 lessThan /sup greaterThan ) in the DPPH free radical scavenging assay. Additionally, both lessThan i greaterThan A. fragrantissima and N. retusa lessThan /i greaterThan extracts showed antiviral activity against Rotavirus Wa, Adenovirus type 7 and Coxsackievirus B4. Further research is needed to elucidate the active constituents of both plants which may be useful in the development of new and effective antioxidant and antiviral agents. AMAL A. MOHAMED , SAMI I. ALI , FAROUK K. EL-BAZ AND WALED M. EL-SENOUSY Antioxidant activity, antiviral, astrovirus, DPPH, ion chelation, rotavirus. 708-722