Lingering Cough - Stuck Phlegm

INGREDIENTS

Each pill contains the equiv. to dry:

Zhejiang Fritillary, bulb 54.5mg

Purple Aster, root 54.5mg

Swallowwort, rhiz. 54.5mg

Stemona, root 36.3mg

Jingjie, herb 36.3mg

Mandarin, peel 36.3mg

Bitter Orange, peel 36.3mg

Red Tangerine, peel 36.3mg

Balloonflower, root 36.3mg

Licorice, root 30.2mg

Store below 30°C

Contains 200 x 200mg pills.

AUSTL 342372

Made in Australia. (Logo)

Indications: productive wet cough with white, yellow phlegm.

Actions: clear the phlegm, stop the cough.

Dosage: 10 - 15 pills 2 - 3 times per day or as symptoms return.

Children: 6 months an over 1 pill per year of age up to the age of 10 as directed above.

Treat more, not less. Treat sooner, rather than later.

​

​

Zhi Sou San – "Lingering Cough"

Helping the Lungs Finish Recovering After an Infection

A classical Chinese herbal formula traditionally used to relieve persistent cough following respiratory infection by calming irritated airways, clearing remaining phlegm and restoring normal lung function.

What is Zhi Sou San?

Most coughs disappear as the infection gets better.

Some don't.

​

The fever has gone.

The sore throat has settled.

Your energy is returning.

Everyone says you're getting better...

​

...except the cough refuses to leave.

Every conversation triggers another coughing fit.

​

Laughing starts the cough.

Talking makes it worse.

Cold air irritates your throat.

Lying down at night becomes frustrating.

Many people assume the infection is still there.

Often, it isn't.

​

Chinese medicine recognised this stage of illness centuries ago.

​

The infection has largely resolved, but the lungs are still recovering from the inflammation it caused.

​

Zhi Sou San was developed specifically for this stage.

​

At Chiron Medical we call it "Lingering Cough."

​

Because by the time this formula is needed, the illness is usually over—but the cough simply hasn't caught up.

​

A Formula for Recovery

Unlike formulas designed to fight infection, Zhi Sou San focuses on helping the lungs recover.

It assists the lungs to:

• calm persistent coughing

• clear remaining mucus

• reduce airway irritation

• restore normal breathing

• complete the healing process

Rather than suppressing symptoms, it helps the respiratory system return to normal.

Why We Call It "Lingering Cough"

A lingering cough is one of the most common reasons people seek medical advice after recovering from a cold or flu.

Typical symptoms include:

• persistent cough lasting weeks

• throat clearing

• small amounts of difficult-to-clear mucus

• coughing after talking

• coughing after laughing

• coughing after exercise

• mild chest irritation

• occasional chest tightness

Unlike an active chest infection, fever is usually absent.

The lungs simply haven't finished healing.

What Is It Traditionally Used For?

Traditionally, Zhi Sou San is prescribed for persistent cough remaining after an external respiratory illness has resolved.

Today it is commonly considered for supportive management of:

• post-viral cough

• lingering bronchitis

• post-infectious cough

• persistent throat irritation

• chronic throat clearing

• mild residual sputum

• prolonged recovery following respiratory infection

​

The Herbs That Make the Formula

​

For most people, the infection ends before the cough does. Fever settles, energy returns and the sore throat disappears, yet the cough lingers for weeks. This happens because the lungs are still repairing the delicate tissues that were damaged during the infection. Small amounts of mucus remain, the airways stay unusually sensitive and even a deep breath, cold air or conversation can trigger another coughing episode.

​

Zhi Sou San was developed for this stage of recovery. Rather than fighting infection, it helps the lungs complete the healing process by clearing residual mucus, calming airway irritation and restoring normal respiratory function.

Zhe Bei Mu (Zhejiang Fritillary Bulb)

Traditional Role

Zhe Bei Mu forms the foundation of the formula. It helps loosen the small amounts of stubborn phlegm that continue to irritate recovering airways while calming the inflammation that keeps the cough reflex active.

Biomedical Actions

Research demonstrates expectorant, antitussive and anti-inflammatory activity together with protection of respiratory tissues. Experimental studies also suggest regulation of mucus secretion, antioxidant effects and support for recovery of inflamed airway epithelium.

Zi Wan (Purple Aster Root)

Traditional Role

Zi Wan has been trusted for centuries to settle the lingering cough that remains after the infection itself has resolved. It helps clear residual mucus while allowing irritated airways to become less reactive.

Biomedical Actions

Research suggests antitussive and expectorant activity together with anti-inflammatory and antioxidant effects. Studies also demonstrate protection of airway tissues and modulation of inflammatory mediators involved in chronic cough.

Bai Qian (Swallowwort Rhizome)

Traditional Role

Bai Qian helps restore the normal movement of air through the lungs while encouraging remaining mucus to clear naturally. It is particularly valuable when coughing is accompanied by a feeling of chest tightness or incomplete clearing.

Biomedical Actions

Research demonstrates expectorant, bronchodilatory and anti-inflammatory effects together with reductions in cough frequency and improved airway function.

Bai Bu (Stemona Root)

Traditional Role

Bai Bu is one of Chinese medicine's classic herbs for persistent cough. It gently quietens an over-sensitive cough reflex while allowing the lungs to continue clearing themselves as they recover.

Biomedical Actions

Research suggests antitussive, antimicrobial and bronchodilatory activity together with protection of respiratory tissues and support for healthy airway function.

Jing Jie (Schizonepeta Herb)

Traditional Role

Although best known for early respiratory infections, Jing Jie has another important role here. It helps resolve the final traces of inflammation that can keep recovering airways unusually sensitive long after the infection has passed.

Biomedical Actions

Research demonstrates anti-inflammatory, antioxidant and immunomodulatory activity together with support for normal respiratory immune function.

Chen Pi (Mandarin Peel)

Traditional Role

Chen Pi helps restore the smooth movement of both air and mucus through the lungs. By improving normal airway clearance, it reduces the irritation caused by retained secretions while also supporting digestion during recovery.

Biomedical Actions

Research suggests improved mucus clearance, antioxidant and anti-inflammatory effects together with smooth muscle relaxation and support for normal respiratory function.

Zhi Qiao (Bitter Orange)

Traditional Role

Persistent coughing often leaves the chest feeling tight and restricted. Zhi Qiao helps relieve this tension, allowing breathing to become more comfortable as normal respiratory movement returns.

Biomedical Actions

Research demonstrates bronchodilatory activity, smooth muscle relaxation and improvements in respiratory mechanics. Studies also suggest antioxidant effects and regulation of airway smooth muscle tone.

Ju Hong (Red Tangerine Peel)

Traditional Role

Ju Hong specialises in clearing the last remnants of sticky mucus that continue to stimulate coughing. It complements Chen Pi by helping restore healthy airway clearance without excessively drying the lungs.

Biomedical Actions

Research suggests expectorant, anti-inflammatory and antioxidant activity together with regulation of mucus production and support for normal mucociliary clearance.

Jie Geng (Balloonflower Root)

Traditional Role

Jie Geng directs the actions of the formula towards the lungs and throat while helping lift residual mucus from the airways. It also soothes tissues that remain irritated after repeated coughing.

Biomedical Actions

Research demonstrates expectorant, anti-inflammatory and immune-modulating activity together with protection of respiratory mucosa and support for healthy airway clearance.

Gan Cao (Liquorice Root)

Traditional Role

Gan Cao provides a soothing finish to the prescription. It calms irritated airways, protects the lining of the respiratory tract and helps the other herbs work together as a balanced formula.

Biomedical Actions

Research demonstrates anti-inflammatory, antiviral and antioxidant activity together with protection of respiratory mucosa. Glycyrrhizin has also shown immune-modulating effects and may help reduce inflammatory injury within recovering airway tissues.

How the Formula Works

A lingering cough is often a sign that the infection has resolved but the lungs have not yet completed their recovery. The airways remain mildly inflamed, the cough reflex becomes unusually sensitive and small amounts of residual mucus continue to stimulate coughing long after the original illness has passed.

Chinese physicians recognised this stage of illness centuries ago. Rather than continuing to treat the infection itself, they shifted their attention towards helping the lungs repair, clear remaining mucus and return to normal function.

Zhi Sou San reflects that change in strategy. Some herbs help remove the residual mucus that continues to irritate the airways, others calm the overactive cough reflex, while several reduce inflammation and support repair of the delicate respiratory lining. Together they create the conditions needed for the lungs to complete their recovery naturally.

Modern research suggests the formula may improve mucociliary clearance, regulate mucus production, reduce airway inflammation, support respiratory epithelial repair and moderate the heightened sensitivity of the cough reflex. These complementary actions help explain why Zhi Sou San has remained one of Chinese medicine's classic formulas for the lingering cough that persists after respiratory infections have otherwise resolved.

​

How the Formula Works

Following a respiratory infection, inflammation within the airways often persists long after the virus has disappeared.

​

The cough continues because:

• airway nerves remain hypersensitive

• small amounts of mucus continue to irritate the airways

• damaged respiratory tissues are still healing

• the cough reflex remains overactive

Research suggests the herbs within Zhi Sou San may help:

• reduce airway inflammation

• improve mucus clearance

• calm cough sensitivity

• protect respiratory mucosa

• support tissue repair

Rather than treating an active infection, the formula supports the lungs as they return to normal function.

What Does Modern Research Say?

Research into the herbs contained within Zhi Sou San has investigated their role in:

Persistent Cough

Studies suggest supportive effects on:

• frequency of coughing

• airway irritation

• sputum clearance

• patient comfort

Respiratory Recovery

Research demonstrates:

• expectorant activity

• anti-inflammatory effects

• bronchodilation

• antioxidant activity

• protection of respiratory tissues

These findings closely reflect the traditional use of the formula for lingering cough after respiratory infection.

Comparing the Chiron Medical Cough Formulas

Not every cough needs the same treatment.

Recognising the stage of illness is often more important than recognising the cough itself.

​

Sang Ju Yin - New Cough - Early cough during the first stage of respiratory infection - Protects the lungs during early illness

Qing Qi Hua Tan Tang - Wet Cough – Yellow Sticky Phlegm - Thick yellow or green sputum with active chest infection - Clears Heat and infected phlegm

Zhi Sou San - Lingering Cough - Persistent cough after the infection has resolved - Completes recovery by calming the cough and clearing remaining mucus

Bai He Gu Jin Tang - Dry Cough - Dry irritating cough with little mucusNourishes and repairs the lungs

Ding Chuan Tang - Wheeze - Wheezing, chest tightness and asthmaOpens the airways and relieves bronchospasm

Yu Ping Feng San - Immunity - Recurrent respiratory infections - Builds long-term immune resilience

Understanding the Progression

Respiratory illness often follows a predictable pathway.

Colds, Shivers & Sniffles (Gui Zhi Tang)

The illness begins with chills, sneezing and a runny nose.

↓

No.1 Flu, Fever, Virus & Infection (Yin Qiao San)

Fever develops and the body's immune system mounts its first major response.

↓

New Cough (Sang Ju Yin)

The infection begins affecting the lungs and an early cough develops.

↓

Wet Cough – Yellow Sticky Phlegm (Qing Qi Hua Tan Tang)

Inflammation produces thick yellow mucus, indicating active infection within the lungs.

↓

Lingering Cough (Zhi Sou San)

The infection has largely resolved, but airway irritation and residual mucus continue triggering persistent coughing.

↓

Dry Cough (Bai He Gu Jin Tang)

As healing continues, the mucus disappears but dryness and irritation remain.

↓

Immunity (Yu Ping Feng San)

Recovery is complete and attention turns towards strengthening the immune system to reduce future respiratory infections.

Understanding this progression allows treatment to evolve naturally as the illness changes.

For Traditional Chinese Medicine Practitioners

Classical Pattern

Residual External Pathogen with lingering Lung Qi disharmony

Typical presentation:

• persistent cough

• slight residual sputum

• throat irritation

• absence of significant fever

• mild chest discomfort

• normal or slightly red tongue

• moderate pulse

Formula Strategy

Zhi Sou San:

• Stops cough.

• Restores the descending function of Lung Qi.

• Transforms residual phlegm.

• Relieves airway irritation.

• Supports complete respiratory recovery.

For Medical Doctors

Proposed Biomedical Actions

Current evidence suggests the constituent herbs may influence:

• cough reflex sensitivity

• respiratory mucosal inflammation

• mucus clearance

• bronchial smooth muscle tone

• oxidative stress

• airway repair

Collectively these mechanisms may contribute to reduced coughing while supporting recovery of the respiratory tract following infection.

Potential Herb–Drug Considerations

Clinical monitoring is advisable in patients taking:

• cough suppressants

• expectorants

• bronchodilators

• corticosteroids

• anticoagulants

A persistent cough lasting longer than eight weeks, coughing up blood, unexplained weight loss, chest pain or shortness of breath should always be medically investigated.

Helping the Lungs Finish the Job

One of the most frustrating parts of recovering from a respiratory infection is when everything feels better—except the cough.

​

Zhi Sou San recognises that healing doesn't always end when the virus disappears.

Sometimes the lungs simply need a little more help to return to normal.

​

That is why we call it "Lingering Cough."

​

It isn't a formula for fighting the infection.

It's a formula for helping the lungs finish recovering from it.

​

Key Takeaways

• Zhi Sou San (Lingering Cough) is a classical Chinese herbal formula used during the recovery phase of respiratory infections when the cough persists after the fever and acute illness have resolved.

• It helps calm airway irritation, clear remaining phlegm and restore normal lung function without simply suppressing the cough reflex.

• It differs from Qing Qi Hua Tan Tang (Wet Cough – Yellow Sticky Phlegm), which is intended for active chest infections with thick yellow or green sputum and ongoing inflammation.

• Within the Chiron Medical Cough Network, Lingering Cough fills the important gap between acute infection and complete respiratory recovery, helping patients transition from illness back to full health.

• Once recovery is complete, Yu Ping Feng San (Immunity) can help strengthen long-term immune resilience and reduce the likelihood of future respiratory infections.

​

Clinical Insights

Knowing When to Change Formulas

One of the most common mistakes is continuing to use an acute infection formula after the infection has already resolved.

Once the fever has settled and energy has returned, persistent coughing usually reflects recovery, not ongoing infection.

At this stage, practitioners often transition from:

• Yin Qiao San (No.1 Flu, Fever, Virus & Infection)

or

• Qing Qi Hua Tan Tang (Wet Cough – Yellow Sticky Phlegm)

to

• Zhi Sou San (Lingering Cough)

This change reflects the lungs' changing needs.

The goal is no longer to fight infection.

The goal is to complete recovery.

​

If the cough gradually becomes dry and irritating with very little mucus remaining, practitioners may then progress to:

• Bai He Gu Jin Tang (Dry Cough)

Once respiratory health has fully recovered, many practitioners recommend:

• Yu Ping Feng San (Immunity)

to strengthen long-term immune resilience and reduce the likelihood of future respiratory infections.