Benadryl is an antihistamine and is used to treat sneezing, runny nose, itching and other allergies. Learn about side effects, interactions and indications. Benadryl (diphenhydramine) treats allergy and cold symptoms like a runny nose and sneezing, plus allergic reactions such as hives and swelling. Common side effects include sleepiness, dizziness. Improvement in a runny nose during a cold is not due to the anti-histamine properties of the medication. In general, Benadryl ® is not an effective medication to use during upper respiratory infections due to short duration of action and unfavorable side effects. Learn how to stop a runny nose effectively with these tips, home remedies, and medications. Yes, Benadryl can effectively help with a runny nose caused by allergies. It works by blocking histamine receptors, reducing inflammation and mucus production triggered by allergic reactions. Rhinorrhea, or a runny nose, is a common issue people face. Learn more about the symptoms, causes, and treatments associated with rhinorrhea. Yes, Benadryl helps reduce runny nose symptoms caused by allergies. It blocks histamine receptors, which are responsible for nasal irritation and mucus production during allergic reactions. Benadryl Allergy Plus Congestion is a combination medicine used to treat runny or stuffy nose, sneezing, itching, watery eyes, and sinus congestion caused by allergies, the common cold, or the flu. Explore our range of BENADRYL® adult allergy medications. Find effective relief from allergy symptoms like sneezing, runny nose, and itchy eyes. Benadryl (diphenhydramine) does stop a runny nose, and it works faster and more aggressively than most over-the-counter alternatives. But whether it’s the best choice depends on what’s causing your runny nose and how much drowsiness you’re willing to tolerate.