Eucommia
The herb is sweet and pleasant in taste and warming in nature. The bark is the part used.
The Chinese will score the bark in small strips. The inside of the bark is made up of a very resilient resinous sap that has a lot of flexibility to it. This supports the Doctrine of Signatures approach that it is good for joints and tendons and ligaments because it is viscous and helps to hold things together.
Because it has an affinity for the kidneys and the liver meridians, it is indicated in kidney deficiencies, liver deficiencies, dizziness, headaches, weakness and fatigue. It is used for weak painful knees, weakness of muscles and legs (in Chinese medicine considered the lower extremities.) Used for liver and kidney deficiencies with such symptoms as weak, sore or painful lower back and knees. Aids in the smooth flow of Qi (energy) and blood, especially in those with weakness of the sinews and the bones. It is also known to lower blood pressure. No symptoms of overdose have ever been recorded in the literature,.
It has been used over the years for horses with loose and injured stifles to help tighten up the ligaments and tendons of the back knee. It can be used as a support for damage and stress to front leg tendons as well
Chinese Herbal Medicine Materia Medica (compiled and translated by Dan Bensky and Andrew Gamble, Eastland Press, Seattle, 1986).