Chinese herbs and Cough

Effective of Chinese Medicine preparation in the treatment of cough in uncomplicated upper respiratory tract infection

Study: Effectiveness of a Chinese herbal medicine preparation in the treatment of cough in uncomplicated upper respiratory tract infection

Location of trials: Hong Kong

Year of Trial: 2003

Type of Trial: Randomised double-blinded placebo controlled trial

Medical Condition

Acute cough is a common symptom of upper respiratory tract infections (URTI). The subjects in this trial presented the typical variations of cough symptoms including: night cough; sputum; nasal congestion, hoarseness, sore throat and other symptoms experienced with a common cold such as muscle pain, headache; running nose and sneezing.


Tablets containing extracts granules from these herbs were given the TCM group. Placebo tablet given to the control group.

Chuan Bei Mu (Bulbus Fritillariae Cirrhosae) 27.3%, Jing Jie (Herba Schizonepetae) 10.5%,  Fang Feng (Radix Ledebouriellar )10.5%, Jie Geng (Radix Platycodi ) 10.5%,  Gan Cao (Radix Glycyrrhizae) 4.4% , Zi Wan (Radix Asteris) 10.5% Bai Bu (Radix Stemonae) 10.5% , Bai Qian (Rhizoma Cynanchi Stannotonii )10.5% Chen Pi (Pericarpium Citri Reticulatae) 5.3%.

NB: Many subjects were prescribed pharmaceutical medicine at the beginning of the trial. e.g 67 subjects were given Fexofenadine. Paracetamol was given to 44 subjects. Read study paper for full listing of pharmaceutical medications.

Dosage: The dosage was 3 tablets three times a day (each tablet was 500 mg)


Most subjects had a mean of 4 day history of cough. 81 started trial. 19 withdrew before study was completed. Reasons for withdrawing included: worsening symptoms (so had to seek other treatment) : using over the counter cough medicine; the cough improved and stopped before end of trial; conditions changed and antibiotics had to be used. In all cases none of these subjects experienced adverse effects from the formula. Participants were encouraged to withdraw if their symptoms changed or deteriorated.

Outcomes Measured

  1. Leicester Cough Questionnaire – A questionnaire to assess chronic coughs
  2. Cough Score – patient rating of cough severity
Treatment period was 5 days. Assessments and examinations were conducted on day 4 and day 7.


62 patients (75.6%) had completed the trial and no adverse effects were reported. Both intervened and control groups had improved in cough score and LCQ in the follow-up period,= despite no overall statistical significance was observed in the differences of scores between the two groups. Women taking TCM had significantly fewer problems with sputum production (p = 0.03) and older subjects (>35 years of age) reported a significant improvement in hoarseness (p = 0.05) when compared to those using placebo.

Cochrane Quality 

not found


The first question that come to mind is why  allow a variety of pharmaceutical medications to be used on both the TCM and placebo groups? The paper acknowledges that his may have confounding effects on the TCM preparation, which begs the question why do it in the first place? If the primary objective of this study was to test the effectiveness of TCM preparation on cough surely you would control the variables as much as was within your power.

This trial seems to be an attempt at standardising TCM treatments across all subjects using a  common formulation (as it mentions one similar to the Pe PA Kao syrup). An approach to a single formula for all patients contradicts the principles of TCM medicine. We know that when you get a cough you usually have other symptoms and these symptoms can vary from person to person. In TCM the pattern diagnosis determines the treatment and therefore treatments are not the same for each patient. With colds you can narrow it down by reverting to base formulas commonly used for wind-cold, wind-heat attacks or wind-attached etc. However there maybe other symptoms present that warrant formula modifications and failing to address these other symptoms could result in an ineffective treatment or a worsening condition. For example it could be hypothesised that the number of drop outs may have been less if they had been prescribed a formulation based on their individual pattern.

However conducting a trial in which multiple formulations maybe possible if you had large numbers but even then  you would have to question the validity of such a trial where you are testing effectiveness of multiple remedies against the same placebo group. Valid clinical trails need simple valid hypotheses that can be retested. This trial seems an attempt at doing that. However you have to question the unusual decision of allowing subjects to use antihistamines , paracetamol and other drugs.


Wong WCW, Lee A, Lam AT, Li KT, Leung CYM, Leung PC, Wong ELY and Tang JL. Effectiveness of a Chinese herbal medicine preparation in the treatment of cough in uncomplicated upper respiratory tract infection: a randomised double-blinded placebo-control trial:  www.coughjournal.comn/content/2/1/5


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