Sorrels: Which is Medicinal?

Sorrel (Rumex) is said to be used as a remedy and to fight cancer. I noticed you offer 3 varieties of Rumex acetosa (garden sorrel): Blonde de Lyon, Nobel, and Profusion. In addition, you offer: Sheep Sorrel (Rumex acetosella) and True French Sorrel (Rumex scutatus). Is there a difference in the medicinally active properties of these six varieties? If there is no difference I will probably try Profusion since the leaves seem bigger! Otherwise I will want to try the Sheep Sorrel.

It is possible that all six varieties are medicinal. However, the one known to have antitumour properties is Rumex acetosella, the sheep sorrel. This, for example, is the sorrel used in Rene Caisse's anticancer remedy, Essiac.
Sheep sorrel is much smaller and consequently more expensive and harder to find than the garden sorrel. We have noticed that much of the dried sheep sorrel that is on the market is actually garden sorrel. Even some of the biggest herb companies seem to be unaware of the substitution. It is questionable whether garden sorrel has the same effect as sheep sorrel. There are no reports in the medical literature that we are aware of that suggests that garden sorrel has any antitumour effect; although that doesn't necessarily mean it has no such effect.