India, Dec. 3 -- Berlin (dpa) - If you have developed a cough which you're struggling with or is keeping you up at night, don't be tempted to buy special medicine to calm it down. Chemists sell two kinds, basically. Cough suppressants loosen mucus and are intended to make coughing easier. If a dry, irritating cough develops towards the end of a cold, cough suppressants are supposed to provide relief. The other kind of medicine is expectorants, medication to thin and loosen mucus in the airways, aiming making it easier to cough up and clear from the throat and lungs. But testers in Germany question how effective the remedies are, whether herbal or synthetic. All cough suppressants fail In Germany, consumer organization Stiftung Warentest exa...