About the Study

The study was a small randomized crossover trial . In a crossover, each participant is eventually exposed to all of the options that were studied. The 39 participants were all sensitive to grass pollens. They were exposed to this pollen in a special chamber that can deliver measured amounts of pollen. After the exposure the participants were given one of the following:

• Phenylephrine 12 mg
• Pseudoephedrine 60 mg
• Placebo

Over the following six hours, participants were monitored and asked to rate their nasal congestion. At the end of the trial participants reported:

• Significantly better results with pseudophedrine compared to phenylephrine and placebo
• The same results for phenylephrine compared to placebo

Neither medication relieved non-nasal allergy symptoms.

How Does This Affect You?

This was a small study. The larger the study, the more reliable the results will be. Despite this limitation, there is a suggestion here that products containing pseudoephedrine are more likely to effectively relieve your allergy symptoms than those containing phenylephrine. In addition to these over-the-counter medications, your doctor is able to prescribe other medications supported by more convincing evidence of effectiveness.

In general, to help manage seasonal allergies, try to avoid peak pollen times, such as 6am-10am. When doing activities that may stir up pollen (like cutting grass), wear a mask. Learn what times of year your allergies tend to occur and make a plan to begin preventative steps. If you suffer from severe seasonal allergies or have allergic symptoms all year round, you may wish to speak to your doctor about preventive treatments, such as allergy injections .