About gramicidingramicidin is active against most of the gram positive bacteria and some gram negative bacteria. its use is limited to topical use only, since systemic use may produce haemolysis.gramicidin produces its action by increasing the permeability of cell wall. while the permeability increases inorganic monovalent cations enter to the bacterial cell wall and destroy the ion gradient between the cytoplasm and the extra cellular environment.special precautions while taking gramicidin1.use caution while driving vehicle, operating machine and other activities which requires clear vision. 2.patients using contact lens indications for gramicidinbacterial infections of eye