The document discusses various plant species that are used as tonics for human health and immunity. It provides information on over 50 plant species, organized by family, with details on locality, parts used, and functions as tonics. Many of the plants discussed are from Asia, North America, and Europe, and are used to fight infections, strengthen tissues, and improve mental health and harmony. The document advocates for further research on formulations using these plants for immune boosting and as affordable herbal tonics.