The American College of Chest Physicians is now advising those who have colds that over-the-counter (OTC) cough syrups or drops are worthless for their intended purpose.
There is no scientific evidence that either suppressants like dextromethorphan or expectorants like guaifenesin relieve cold-related coughs.
This is similar to the findings of a 2004 paper by the non-profit Cochrane Collaboration, which discovered no good evidence either for or against the effectiveness of OTC cough medicines.
OTC cough medicines do have a strong placebo effect, and coughs from colds eventually go away on their own; consumers may have therefore been led to believe they had personal evidence of the effectiveness of the cough medicines.
Nearly 30 million visits to doctors' offices in America each year are for coughs.
