Some foods that act as natural decongestants include hot mustard, horseradish, cayenne pepper and wasabi, reports Women's Health magazine. These spicy foods help reduce mucus, clear nasal debris and open clogged breathing passages.
Quercetin is a natural anti-allergenic plant pigment that possesses antihistamine qualities, according to the University of Maryland Medical Center. It helps open stuffy air ways and reduces the puffiness associated with allergies and colds. Foods containing quercetin include citrus fruits, apples, onions, parsley, sage, tea, red wine, olive oil and dark berries, such as cherries, blueberries and blackberries.
Nettles have been used for many years as an antihistamine, says Women's Health magazine. The plant can be used in many recipes or brewed as a tea.