Salem, Mohamed AZayed, AhmedEzzat, Shahira M2021-03-082021-03-0803/05/2021https://doi.org/10.1016/B978-0-12-821556-2.00023-2https://qrgo.page.link/3DUHiAllergic diseases such as allergic asthma, hay fever, dermatitis, food, and drug allergies have increased tremendously in the last decade with increased morbidity. The current antihistaminic drugs have some limitations in terms of safety and efficacy. Most of the allergic conditions are chronic and long-term therapy is essential. Therefore, most allergic patients seek better alternatives to synthetic antihistaminic agents. Several plants and their derived natural products have been reported as effective, safe, and cheap antiallergic agents. Additionally, several plant-derived formulas have reached the clinical trials as safe antiallergic, with similar mechanisms to synthetics drugs. In this chapter, we highlighted the relevant use of plants from folk medicine or scientific-based evidence for natural antiallergic drugs. Special emphasis is given on the natural compounds with reported antiallergic activity.en-USAntihistaminic plantsAllergyQuercetinCatechinFlavonesTriterpenesBook chapterhttps://doi.org/10.1016/B978-0-12-821556-2.00023-2