| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Rubus idaeus | Leaf | 0.2 | 1.3 | -0.4 | * |
| Rubus chamaemorus | Fruit | 10.0 | 62.0 | -0.4 | * |
| Rumex crispus | Root | 0.3 | 1.3 | -0.3 | * |
| Ruscus aculeatus | Root | 7.0 | 22.4 | -0.2 | * |
| Salix alba | Bark | 0.5 | 2.9 | -0.5 | * |
| Salvia officinalis | Leaf | 0.5 | 3.1 | -0.4 | * |
| Schisandra chinensis | Fruit | 0.5 | 3.4 | -0.6 | * |
| Scutellaria lateriflora | Plant | 0.7 | 4.8 | -0.5 | * |
| Senna alexandrina | Leaf | 2.0 | 10.7 | -0.4 | * |
| Serenoa repens | Fruit | 1.0 | 7.8 | -0.6 | * |
| Silybum marianum | Plant | -- | -- | Pedersen, M. 1987. Nutritional Herbology. Pederson Publishing. Bountiful, Utah. 377 pp. | |
| Silybum marianum | Leaf | -- | -- | * | |
| Smilax officinalis | Root | 2.0 | 8.8 | -0.3 | * |
| Smilax spp | Root | 2.0 | 8.8 | -0.3 | * |
| Solanum tuberosum | Tuber | 1.0 | 10.0 | ACTA AGRIC SCAND SUPPL 22: 1980 | |
| Sorbus aucubaria | Fruit | 20.0 | 190.0 | 0.0 | * |
| Spinacia oleracea | Leaf | 1.0 | 855.0 | 2.1 | ACTA AGRIC SCAND SUPPL 22: 1980 |
| Spirulina spp. | Plant | -- | -- | * | |
| Stachys officinalis | Plant | 1.3 | 8.0 | -0.5 | * |
| Stellaria media | Plant | 0.5 | 5.7 | -0.5 | * |