Zhi Sou San (Powder to Stop Coughing) zhǐ sòu sǎn · 止嗽散

Safety. The formula was written for the tail end of an exterior pattern, when the wind has largely gone and a cough lingers; it is not intended for the acute, febrile stage, and a cough that lasts more than a few weeks, or comes with weight loss, breathlessness or blood, is a reason to seek conventional assessment rather than a traditional formula. Two of its herbs carry real cautions. Stemona (百部) has documented reports of nausea and vomiting with inappropriate use, and larger exposures have been reported to depress respiration; it is a herb where the difference between a dispensed amount and a household guess is not academic. Aster root (紫菀) belongs to a genus in which pyrrolizidine alkaloids have been reported; that is not a reason to panic over a short supervised course, but it is a reason not to use it long-term or unsupervised, and to avoid it in pregnancy and in existing liver disease as a precaution. Platycodon and cynanchum can both provoke nausea in sensitive stomachs. Schizonepeta is a mild sweat-promoting herb, which is why the formula is aimed at the lingering rather than the acute stage. Licorice carries the usual cautions. Amounts are deliberately not given here.