Rice-paper Plant Pith tōng cǎo · 通草

Safety. The caution that matters here is about the name, not the herb. Tong cao is the pith of Tetrapanax and is not the same drug as mu tong or guan mu tong. Guan mu tong is Aristolochia manshuriensis, which contains aristolochic acid, a substance known to damage the kidneys and to cause cancer of the urinary tract; its use is prohibited in many countries. Because the names look alike in Chinese and in translation, nothing should be taken under either name until a qualified professional has confirmed which plant it actually is. Tong cao itself is classically avoided in pregnancy. Its traditional uses are not established by modern research.