Herbal cough syrups: do they work and when a cough is not for tea

Not all herbal syrups are equal. The most solid data are for the thyme and ivy combination: a trial with double-blind placebo control (a scientific method for testing medicines, in which neither the patients nor the doctors know who receives the real treatment and who a dummy pill) in acute bronchitis (Kemmerich and colleagues, 2006) showed that the fluid extract of the two herbs shortens cough significantly more than placebo. Ivy also has studies in children for relieving cough in acute respiratory infections and bronchitis, showing good safety and efficacy in reducing the severity and duration of cough, and thyme is approved by the European agency for traditional use in cough and sore throat.

Something that surprises many parents: the best studied natural remedy for night cough is honey. The Cochrane review in children found that honey reduces cough frequency better than placebo and is present in commonly used pharmacy products. One teaspoon before bedtime can help, but never in children under 1 year because of the botulism risk.

Echinacea has no proven effect on cough, even though it is put into most immune syrups. Elderberry syrups have studies only in influenza, not in an ordinary cough. And combination syrups with ten herbs at once have not been studied as the specific mixture, because trials are expensive and manufacturers do not want to invest millions in testing the final combined blend.

Remember the paediatric rule as well: sedative cough medicines such as codeine are not given to children, and in small children a cough is treated mainly with humid air, fluids and patience, not with syrups.

Herbal care is appropriate only for a mild cold. See a doctor, urgently if needed, if any of the following appears: shortness of breath or wheezing, a cough that does not ease for more than 2 weeks, fever for more than 3 days, chest pain, blood in the sputum. In a child the warning signs are refusal of food and fluids and indrawing of the spaces between the ribs when breathing. In babies under 3 months every cough is a reason for an examination.

And most importantly from practice: if the cough does not ease within 5-7 days or returns after improvement, do not switch one tea for another. Seek a diagnosis, because pneumonia is not treated with thyme.

The information in this article has been verified and is based on: the double-blind placebo-controlled trial by Kemmerich et al. on thyme and ivy in acute bronchitis (2006), the Cochrane review on honey for acute cough in children and the systematic review of clinical trials on herbal cough syrups (PMC, 2010).