Che Qian Zi (车前子) — Plantain Seed | TCM Dampness-Draining & Eye Herb Guide

At a Glance

Herb: Che Qian Zi
Chinese name: 车前子 (Chē Qián Zǐ)
Latin name: Plantago asiatica L.
Nature: Cold
Taste: Sweet
Meridian: Kidney / Liver / Lung / Small Intestine
Category: Herbs that Drain Dampness
Introduction: Che Qian Zi (车前子), plantain seed (Plantago asiatica / P. depressa), is a versatile water-draining herb with an unusual three-directional action: it drains dampness through urination, clears liver heat to brighten the eyes, and transforms lung phlegm to relieve cough. Its name (‘carriage-front seeds’) refers to the plant’s habit of growing in wheel ruts. Entering the Kidney, Liver, Lung, and Small Intestine channels, its most clinically notable property is treating diarrhea by diverting water to the bladder (‘利小便以实大便’ — promote urination to solidify the stool). Aucubin and plantaginin provide its diuretic, anti-inflammatory, expectorant, and ocular-protective effects.

Promotes urination and drains dampness (利水通淋): treats edema, urinary difficulty, and painful urinary dribbling (lin syndrome).
Separates the clear from the turbid to stop diarrhea (分清止泻): the famous principle of diverting damp to the bladder to firm up loose stools — treats summer damp diarrhea.
Clears liver heat and brightens eyes (清肝明目): treats red, painful, or dry eyes from liver heat or liver-kidney deficiency.
Clears lung heat and transforms phlegm (清肺化痰止咳): treats lung heat cough with yellow sputum and difficult expectoration.

Urinary tract infections: painful, burning, scanty urination from damp-heat lin syndrome — combines with Hua Shi, Mu Tong, Zhi Zi (Ba Zheng San).
Summer damp diarrhea: loose stools from dampness in the intestines — diverts water to bladder, firming the stool (Wu Ling San variant).
Eye disorders: red eyes, cataracts, blurred vision from liver heat or deficiency — combines with Ju Hua, Gou Qi Zi.
Edema: generalized or lower-body edema — promotes urination to resolve damp.
Lung heat cough: productive cough with yellow phlegm — with Sang Bai Pi, Huang Qin.
Urinary stones: promotes passage with high fluid intake.

Kidney yang deficiency without damp-heat: use cautiously — cold draining nature further depletes yang; add warming herbs.
Pregnancy: traditionally cautioned in high doses — strong downward draining action.
Decoction method: must be wrapped in cloth (包煎) during decoction — tiny seeds clog the strainer and absorb liquid excessively if not wrapped.
Standard dose: 9–15g in decoction (包煎).

八正散 (Ba Zheng San): Che Qian Zi + Hua Shi + Mu Tong + Zhi Zi — damp-heat lin syndrome; UTI with painful burning urination; from 《太平惠民和剂局方》.
五苓散 (Wu Ling San) variant: Che Qian Zi added for stronger diuretic action and damp-diarrhea.
驻景丸 (Zhu Jing Wan): Che Qian Zi + Ju Hua + Shu Di + Tu Si Zi — liver-kidney deficiency with eye disorders and visual decline.
济生肾气丸 (Ji Sheng Shen Qi Wan): Che Qian Zi + Niu Xi + Jin Gui Shen Qi Wan base — kidney yang deficiency edema with dysuria.

For damp-heat urinary difficulty and painful urination: combine with Mu Tong, Hua Shi, Gan Cao Shao (Ba Zheng San).
For kidney deficiency edema: combine with Fu Ling, Ze Xie, Rou Gui (Ji Sheng Shen Qi Wan).
For summer-heat with diarrhea (利小便以实大便): use alone or with Bai Zhu.
For liver heat with red eyes: combine with Ju Hua, Jue Ming Zi, Long Dan Cao.
For lung heat cough with phlegm: combine with Sang Bai Pi, Huang Qin, Gua Lou.
For kidney deficiency with turbid urine: combine with Tu Si Zi, Fu Ling, Shan Yao.
For urinary stones: combine with Jin Qian Cao, Hai Jin Sha, Niu Xi.

Diuretic
- increases urine output and electrolyte excretion without depleting potassium
Antidiarrheal
- mucilage absorbs excess water in intestines
- paradoxically stops damp-type diarrhea
Expectorant
- stimulates respiratory mucus secretion, thins phlegm
aucubin
- Anti-inflammatory: inhibits NF-κB and reduces inflammatory cytokines
Hepatoprotective
- reduces liver enzyme elevation in toxic injury
potassium content and vasodilatory flavonoids
- Antihypertensive: lower blood pressure
Ocular protective
- reduces intraocular pressure in glaucoma models

Shen Nong Ben Cao Jing (《神农本草经》): ‘Governs qi strangury, stops pain, promotes the waterway and urination, and eliminates damp impediment; long-term use lightens the body and resists aging.’
Ming Yi Bie Lu (《名医别录》): ‘Center injury in men, dribbling strangury in women, loss of appetite; nourishes the Lung, strengthens yin, and benefits essence, enables conception, brightens vision, and treats red painful eyes.’
Ben Cao Gang Mu (《本草纲目》): ‘Conducts heat from the Small Intestine and Bladder; Lung qi descends and the waterway opens, promoting urination without dissipating qi.’
Ben Cao Jing Shu (《本草经疏》): ‘Plantain Seed governing qi strangury, stopping pain, facilitating the waterway, and promoting urination — this is because its flavor is sweet and cold, its qi descends, and it can drain damp-water pathogen.’