The antiviral activity of plants Silybum marianum (seeds), Chenopodium album (whole plant) and Nigella sativa (seeds) were evaluated against Peste des petitis ruminants virus (PPRV) and Foot and Mouth Disease virus (FMDV) in this study. Methanolic extraction of these plants was done by using Soxhlet apparatus and extracts were dried by using rotary evaporator. Vero cells were infected by PPRV and BHK-21 by FMDV respectively. The herbal extracts assays of antiviral and cytotoxic were carried out in cell culture plates. MTT [3-(4,5-dimethylthiazol 2-yl)-2,5-diphenyltetrazolium bromide]...