We have previously reported the ability of the aqueous extract of Bixa orellana (AEBO) in suppressing inflammation
induced by carrageenan (data not published) and bradykinin [6]. This study aimed to investigate whether the anti-inflammatory activity of AEBO was caused by the blocking of histamine action, and to determine the involvement of two biochemical mediators, NO and vascular endothelial growth factor (VEGF), in the reduction of inflammation by AEBO.