In recent years, the emergence of drug-resistant pathogens and the limitations of current therapies have highlighted the need for innovative strategies to combat emerging viral infections. Natural compounds, derived from plants, are playing an increasingly significant role in the research of novel and effective therapies. Boswellia sacra, a frankincense-producing tree widely distributed in Yemen and Oman, and Nerium oleander, a common ornamental and medicinal plant, are examples of plants with well-documented antimicrobial properties. Their extracts have demonstrated good activity against a wide range of infections, which is attributed to the anti-inflammatory and immunomodulatory compounds they contain. Based on these findings, we assessed, in vitro, the broad-spectrum antiviral activity of combined extracts obtained from Boswellia sacra and Nerium oleander. The extract mixture NOBS7(1) was found to be active against the respiratory virus RSV, Herpesvirus simplex type 1, and Coxsackievirus 5. Furthermore, a combination of cell-based assays was performed to provide additional insights into their potential mechanism of action.