Flavonoids polyphenolic compounds that exert many anti-inflammatory and anti-microbial effects, and exhibit an anti-allergic action. Quercetin is a flavonoids that recently has raised many issues and shown evidence about its action as a potential drug to allergy. A Chinese herbal formula, known as Food Allergy Herbal Formula (FAHF) has been related with blocking of anaphylaxis to peanuts (PNA) in mouse models. Quercetin appears to possess the same potential of FAHF as a safe anti-allergic substance but it opens only a wide perspective, at the moment, due to several complex issues that hamper the possibility to use natural medicine and phytochemicals as true drugs.