If you use a steroid inhaler like Advair for asthma or COPD, rinse, gargle and SPIT immediately after inhaling. Not rinsing heightens the risk of thrush, but swallowing the stuff puts steroids where they don't need to be. I used to follow my morning puff with a swig of coffee until my doctor put me straight! If you do get thrush (candida) a course of probiotics can help, as can eliminating sugar from your diet. If a plain water rinse doesn't work, try using mouthwash--either a commercial brand, or try putting a few drops of tea tree oil in the water, or use one part cider vinegar to two parts water.