Rumex is one of those remedies used very specifically.
It is called for when sufferers have a specific type of cough in which they cough on the slightest inhalation of cold air when they breathe in. Because of this they may wrap a scarf around their mouth to reduce the coldness as they inspire to try and stop the coughing.
The cough causes great pain in the chest and sometimes is accompanied by continual attempts to cough up mucus.
Worse breathing in cold air
Cough
Sore throat