Syntheses were conducted of novel benzimidazole derivatives that suppress histamine release from mast cells, inhibit 5-lipoxygenase, and possess antioxidative action. Among the compounds synthesized, 1-[2-[2-(4-hydroxy- 2,3,5-trimethylphenoxy)ethoxy]ethyl]-2-(4-methyl-1- homopiperazino)benzimidazole (22) potently suppressed histamine release from rat peritoneal mast cells triggered by the antigen-antibody