The research paper states, "There is a great need to find broadly acting antiviral agents that would lower the infectivity of viruses around us and that could complement the vaccines and drugs in the combat against viruses. Natural products are a rich source of bioactive compounds." Antiviral Agent From Nature The researchers cut willow bark into small pieces, froze and ground them, and then created an extract using hot water. After treating SARS-CoV-2 virus with the willow bark extract and incubating it with cells, RNA was extracted from the cultured cells for analysis.