| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Scutellaria lateriflora | Plant | -- | -- | Newall, C. A., Anderson, L. A. and Phillipson, J. D. 1996. Herbal Medicine - A Guide for Health-care Professionals. The Pharmaceutical Press, London. 296pp. | |
| Scutellaria lateriflora | Shoot | -- | -- | * | |
| Rehmannia glutinosa | Root | -- | 1100.0 | * | |
| Picrorhiza kurrooa | Juice | -- | -- | * | |
| Verbascum thapsus | Shoot | -- | -- | * | |
| Verbascum thapsus | Plant | -- | 50.0 | * | |
| Euphrasia officinalis | Plant | -- | -- | * | |
| Plantago major | Leaf | -- | -- | * |