An expectorant is a compound with the ability to loosen the mucus secretions in the respiratory tract thus facilitating the process of expectoration - that is, the coughing up and spitting out of sputum.
Although the science behind expectorants is controversial to say the least, these compounds are the basis of a multi- million pound industry, with the public gaining some benefit, probably as much from the placebo effect as any pharmacological action.
Many subemetic doses of drugs acting on the gastric mucosa have been used in the belief there will be a reflux action stimulating the cough reflex, but there is little evidence that they do.
Many so called expectorants are sub-emetic doses of emetics - ipecacuanha, ammonium chloride and squill.
Last reviewed 01/2018