In the very early 70's when I was 12 and 13, my mom would take me to the hospital at Fort McPherson when I had a bad cough. The pharmacy there would give us something nicknamed "G.I. Gin". It was nasty and would kill or cure you.
Funny you should ask. Ive just had about 6 weeks of coughing, no other cold symptoms just the cough. I only do natural remedies snd Ive been doing a bunch of experimenting. What has worked well for me is onions boiled with with a bit of water and good bit of honey. Every few hours i take a couple spoons full. Also make a poultice of onions, put on chest and use a heating pad on top of it.. works wonders. All the other formulas mentioned have merit as well.
Tablespoon of lemon juice, 2 tablespoons of honey, 3 tablespoons of bourbon. Heated to mix, then a tablespoon every few minutes. Granny added molasses to hers.
Kids dose only had 2 tablespoons of bourbon.
Still using it today, made some for the wife twice this week.