Do millions of coughing Americans swallow icky-tasting elixirs each year for nothing? According to a report in the British Medical Journal (BMJ), there is little hard scientific evidence that syrups and other remedies actually stop a cough. In fact, nine out of 15 studies found that cough medicine was no more effective than a placebo. Of course, since the report was published, some doctors have found flaws in the BMJ article and argued that cough medicines really do work.

Who should you trust? Try your own good judgment.

First, ask why you're coughing, says pharmacist Cynthia LaCivita, a pharmacist with the American Society of Health-System Pharmacists. Allergies and even some prescription drugs can produce a cough, in which case guzzling any old syrup probably won't help.

If you have a cold, your cough is likely caused by mucous secretions in the airway. While an expectorant (found in most cough syrups) may help clear those secretions, LaCivita says exposure to moisture will thin and loosen them up even more. When her kids develop a cough that comes with a case of the sniffles, LaCivita simply turns on a humidifier and gives her children plenty of clear fluids and cough drops.