Knowledge Shot: What over-the-counter medicine works best at kicking the cough of the common cold and bronchitis

The common cold causes a sore throat, headache, sneezing, a runny nose or nasal congestion, and coughing which usually starts a few days after the other symptoms, but often develops into the worst symptom and can linger for a few weeks.

Bronchitis causes chest congestion, shortness of breath, wheezing, and once again, a lingering cough.

Both are viral infections so antibiotics don’t work, but the symptoms can be rough, so, what’s the best medication for treating a cough due to the cold or bronchitis?

Unfortunately, many over-the-counter cough remedies haven’t been recently tested and when they have been, many are found to be ineffective.

Also, simply taking something for a cough can make a person feel better, so there’s also a placebo effect at work.

In general, there are three ways to study how well a cough medication works.

The first way is a survey that simply asks people if a medication helped them recover from their cough.

The second way is called the challenge method because healthy people are challenged with citric acid or capsaicin—the molecules that make hot peppers hot—both of which can induce coughing.

Then the medication is given to see if it reduces the coughing.

The third way, cough counting, involves a person with a cough wearing a recording device that counts the number of coughs they have before and after they take a medication.

This last way is considered the best (yes, really) by regulatory agencies like the Food and Drug Administration, but the results don’t always correlate with results from surveys and challenge studies.

So, with this in mind, a recent review in the British Medical Journal took a look at the effect of various over-the-counter cough medications by looking at all three types of measurements.

Now, the availability for each medication varies by country.

For example, codeine is only available with a prescription and Levodropropizine is not readily available in the United States.