| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Psidium guajava | Fruit | -- | -- | * | |
| Petasites japonicus | Plant | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. | |
| Ribes nigrum | Fruit | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. | |
| Eucalyptus globulus | Leaf | -- | -- | Guenther, E., The Essential Oils, 6 volumes, D. van Nostrand, New York, 1948-1952. | |
| Camellia sinensis | Leaf | -- | -- | * |