What is Tong Cao? Are Mu Tong, Guan Mu Tong, Chuan Mu Tong, Deng Xin Cao and Xiao Tong Cao the same?
Official Tong Cao (通草) is the dried stem pith of Tetrapanax papyrifer. The pharmacopoeial name is Tetrapanacis Medulla, also called Bai Tong Cao. Mu Tong is a stem (now usually Chuan Mu Tong or Akebia): bitter-cold, clears Heart fire and promotes urination—not pith. Guan Mu Tong contains aristolochic acid and is banned—never treat it as Tong Cao. Deng Xin Cao is Juncus pith, lighter at clearing Heart fire. Xiao Tong Cao is Stachyurus or Helwingia pith, similar but weaker. Write Tong Cao; do not dispense Mu Tong or Guan Mu Tong.
What are the TCM properties and traditional uses of Tong Cao?
According to the Chinese Pharmacopoeia, Tong Cao is sweet, bland and slightly cold, enters the Lung and Stomach channels, and acts to clear heat and promote urination, and unblock qi to promote lactation. It is used for damp-heat strangury, edema with scant urine, and failure of breast milk to descend. Sweet-bland and thin in qi, its diuretic and lactation-promoting action is mild—suited to mild damp-heat and postpartum scant milk, not to dual qi-Yin vacuity without damp-heat or large doses in pregnancy.
How is the decoction piece used? Can it be drunk long-term as a “lactation herb”?
Cut thick slices into the decoction; it is light, so the weight is small. To promote lactation it is often paired with pig’s trotter or Vaccaria and pangolin scale under a practitioner. It is not a four-season diuretic tea. Dual qi-Yin vacuity and middle cold without damp only grow more vacuous when drained.
What is the usual dosage? Can it be drunk daily as a lactation or diuretic tea?
The pharmacopoeial decoction dose is 3–5 g. It is not a daily “Tong Cao milk tea.” Those without damp-heat whose milk already flows do not need it. Damp-heat strangury and postpartum scant milk need a practitioner to assess causes, including mastitis and latch problems.
What are the contraindications? Can it be used in pregnancy?
Use with caution in pregnancy (explicit in the Pharmacopoeia). Unsuitable in dual qi-Yin vacuity and middle cold without damp-heat. Tell the practitioner if Western diuretics are in use. Never treat Guan Mu Tong as Tong Cao. Stop and return if palpitations, fatigue or a sudden surge in urine appear.
Can Tong Cao promote urination and lactation?
It can help mild damp-heat difficult urination and postpartum scant milk. Damp-warmth joins apricot kernel, coix, white cardamom, lophatherum, talcum, Magnolia and Pinellia in San Ren Tang. Promoting lactation often joins Vaccaria, pangolin scale and angelica. Sweet-bland and thin, it is not a specific for every edema, every low milk supply or every strangury. High fever with bloody urine and a hot red painful breast are emergencies.
Can Tong Cao be drunk daily as a lactation or anti-swelling tea?
Postpartum scant milk and damp-heat dark urine may enter a short formula; dual qi-Yin vacuity only grows more vacuous. “Tong Cao always brings milk” does not replace lactation support and breast examination. Clearing heat, promoting urination and unblocking qi to promote lactation should name Tong Cao (not Mu Tong, not Guan Mu Tong) and a 3–5 g dose.
How do you choose among Tong Cao, Mu Tong, Deng Xin Cao, Hua Shi and Wang Bu Liu Xing?
Rice-paper pith is sweet, bland and slightly cold: clears heat, promotes urination and unblocks qi to promote lactation—mild and less injuring to Yin. Chuan Mu Tong is bitter-cold: promotes urination, clears Heart fire and promotes lactation—stronger. Juncus pith is sweet, bland and slightly cold: clears Heart fire and promotes urination—even lighter. Talcum is sweet-bland-cold: promotes urination, unblocks strangury and clears summerheat—summer-damp. Vaccaria is bitter-neutral: invigorates Blood, unblocks the channels, promotes lactation and disperses swelling—Blood-aspect lactation. Mild damp-heat and promoting milk favor Tong Cao; Heart-fire mouth sores with dark urine favor legal Chuan Mu Tong; vexation with poor sleep favors Deng Xin Cao; summer-damp strangury favors Hua Shi; static scant milk favors Wang Bu Liu Xing. They may be paired; pregnancy cautions Tong Cao and Mu Tong; Guan Mu Tong is banned; the names must not be mixed.
Which herbs is Tong Cao combined with? What are the representative formulas?
Early damp-warmth joins apricot kernel, white cardamom, coix, lophatherum, talcum, Magnolia and Pinellia in San Ren Tang. Damp-heat strangury joins Mu Tong, talcum and plantago seed. Postpartum scant milk joins Vaccaria, pangolin scale, angelica and astragalus. Write Tong Cao; do not dispense Guan Mu Tong or Mu Tong.
How do you choose and store Tong Cao?
Choose white or pale-yellow, light and spongy pith with a silvery fracture, a hollow or ladder-like film center, faint odor and a bland taste. Yellow moldy, hard solid and dirty lots are discarded. Store dry. Buy pharmacopoeial Tong Cao; do not replace clearing heat, promoting urination and unblocking qi to promote lactation with Mu Tong, Guan Mu Tong or Juncus by equal weight.
