And the supply of the drug from nature resources, yew trees and African fern pine( Podocarpus gracilior Pilger), which are grow very slowly and contain only a small amount of taxol, is very limited.

• 并且它的自然资源---红豆杉和东非罗汉松（999年测知含紫杉醇）--都生长地十分缓慢，数量有限且其中有效成分的含量非常低。