Using Fura-2AM microfluorimetry we have shown that 5-lipoxygenase specific inhibitor antiasth-matic agent zileuton significantly suppresses Ca2+-responses induced by immunomodulators glutoxim and molixan in macrophages. The results suggest 5-lipoxygenase involvement in the effect of glutoxim and molixan on intracellular Ca2+ concentration in macrophages and indicate the in-advisability of a combined use in clinics of drugs glutoxim or molixan and antiasthmatic agent zileuton.