Used it last winter when my Appy got a cough - it did work but I had trouble getting him to eat it as it smelt really strong and it was really difficult to disguise the flavour.
Thanks spotty pony my cob will eat anything so not bothered about that. He has an ongoing cough that does go by soaking hay but not quite gone enough so think I'm going to try the herb one
I use the NAF Easy Breathing and it works a treat on my 22 year old mare. Before using, every time I rode in the school she would always without fail have a good old cough after our first trot. Since using it she doesn't cough at all.