Janus faced oxygen radicals are secondary messengers of intracellular signal transduction pathways but also cytotoxic agents of cells. Activation of signal transduction proteins on mild oxidant stress and metal elements are still not clearly understood. Oxygen free radicals may have several functions in the expression of cytokines associated with inflammatory bowel disease. The molecular mechanism between activation, and inhibition participants of signal transduction are delicately controlled. Antioxidant-prooxidant balance of the cells can be traced back to the concentration of free-SH and its oxidised form,-S-S-. Healthy erythrocytes and plasma are rich in antioxidants, but their type of protection, differs significantly. The balance of free radicals and antioxidants is disturbed in inflammatory bowel disease. The antioxidant defence mechanism depends on concentration of metal elements, which determines enzyme activities. It seems that nutritional supplementation and adequate therapy restore the ion homeostasis, although, Zn overdose may cause disturbance in iron metabolism and consequently may influence erythrocyte functions.