Medulla Tetrapanacis (Tong Cao, 通草) is the dried white, spongy pith taken from the stem of the rice-paper plant, Tetrapanax papyrifer. Its name literally means "the unblocker" — a gentle, light herb whose defining action is to open and free the body’s passages, particularly the flow of milk and of water.
Sweet, bland, and slightly cold in nature, Medulla Tetrapanacis enters the Lung and Stomach channels. It is one of the most trusted herbs in Traditional Chinese Medicine for promoting lactation, and it also promotes urination and clears damp-heat. Its mild, unblocking character — moving without depleting — makes it especially well suited to nursing mothers, where it helps support a smooth, abundant flow of breast milk. This gentle, supportive nature is why it features so often in postpartum and confinement soups.