I had one of those dry, hacking, painful coughs you can only get courtesy of air travel. Going from sunny, warm Austin to damp, cold England didn’t help. Cough drops hadn’t helped. Desperate, I ducked into a chemist’s shop and stared at rows of unfamiliar labels. The experienced clerk made two helpful suggestions – cups of hot Scottish breakfast tea with milk and sugar, and a wonderful local cough syrup made with honey, vinegar, and something called ‘glycerol.’
Back in the US, I discovered ‘glycerol’ was food-grade glycerin – I had used it in cooking but never thought of it as a throat remedy.