Ever consider it might be more than a cold? Sounds suspicious because a dry cough as a result of a cold more than likely would have other symptoms. However, if you think it's left over from the cold try "Simply Saline" by Blairex Laboratories, sold at Walgreens. It is pressurized salt water than you inhale through your sinuses and it works miracles for colds, congestion, asthma, alergies, and coughs. You'll never go back to the drugs after trying this natural cure.