A 2015 review says antihistamines have a limited beneficial effect on the severity of cold symptoms for the first two days of a cold, but no benefit beyond that, and no significant effect on congestion, runny nose, or sneezing.

Do antihistamines help congestion?

While antihistamines can't block every allergy symptom, they're particularly effective at preventing nasal congestion and helping some of those uncomfortable symptoms ebb away.

What can antihistamines help with?

Antihistamines are medications that help with allergies, and also with stomach problems, cold, anxiety and more. Antihistamines are a class of drugs commonly used to treat symptoms of allergies. These drugs help treat conditions caused by too much histamine, a chemical created by your body's immune system.