Horsetail, Comfrey, Oatstraw, and Lobelia. Labeled for external use due to comfrey*. Calc Tea formula is a wonderful all natural calcium formula. As explained in the book, Biological Transmutations, the silica in horsetail grass converts to calcium. The other herbs work in close conjunction with this master calcium herb. We need calcium to build strong nerve sheaths, vein and artery walls, bones, teeth, etc. This combination is helpful for cramps, "Charlie horses," successful pregnancies, healthy bones, teeth, hair, skin and nails, healthy eyes and for all calcium needs in the body Available in bulk cut and powder.