w., p.o.)of A. lebbeck stem bark exhibited excellent antiallergic activity in toluene-2,4-diisocyanate- (TDI-) sensitized allergy model Brown Norway rats and HeLa cells expressing endogenous H1R with a significant decrease in the numbers of sneezing, nasal rubbing, and mRNA expression which have been found to elevate TDI-induced H1R and HDC, although the least doses of extract (0.1 to 10 μg/ml) also reduced PMA- or histamine-induced upregulation of H1R mRNA in HeLa cells [48]. This evidence concerns the gene HRH1 and allergic disease.