There is also a product called 'respi-free' available at mose horse tack/supply locations. It is all natural/herbal and can also help provided the problem is not chronic. I would consult your vet first to ensure it is not the beginning of heaves or something more serious. Also I would be careful with ventipulman.....if you administer vent to you horse and then ride them in a dusty environment (indoor arena with other horses) you are only opening up your horses airways to welcome the dust to enter directly into your horses airways and lungs...i'd only administer vent if your horse is in a non dusty envir...or being ridden outdoors. Further do not administer liquid vent by pumping it into a dusty feed such as grain or ground flax as this also will only open up your horses airways to directly suck the dust from the feed into his/her airway/lungs
Hope this helps.