More than eight years ago I was hit in the face in the area of my right eye with a line drive softball while playing short-stop. Within a week I also got bronchitis. When my face healed and my bronchitis went away, I was left with a chronic cough. I mention the softball injury because one of the theorys entertained was damage to my sinuses. I have seen ent, cardio-pulmonary, allergists, etc, even the three day mayo clinic special. Some of the diagnosis: chronic sinusitis, post nasal drip, acid reflux (from hiatal hernia). Some unsuccessful treatments: steroid (prednisone), inhalers, tessulon pearls, a type of tussin, zantac and prilosec (the reflux theory).None greatly successful, inhalers made it worse since inhaling anything foreign into my lungs can cause the cough. Examples: strong scents such as perfumes, pot-pouri, extreme hot and cold temps. Sounds like asthma but I have been tested four times and each time found negative. My favorite diagnosis is reactive airways disease, a nice catch all diagnosis, translation: we have no idea why you cough but your airways are reacting. Obviously. Mayo said, your cough irrates your throat and your throat makes you cough. They told me to take baby coughs. I told them to take baby farts. What helps? Extreme success with Dimetapp liquid. My doctor and I also discovered, while taking Ultram, a non-narcotic prescription pain reliever, that I coughed less. His explanation was that some types of pain meds can dull the receptors in your lungs. I take one in the morning and one at night, most days. It helps. I don't believe any of the doctors really know what is wrong. The up side, it's not cancer, I'm still alive, I just cough. Smoking is not an issue. Did grow up in a smoking household though. From this site, I see there are a lot of folks coughing chronically and every doctor calls it something different.