Introduction:Colloidal silver and nanoparticles (AgNPs) are used to disinfect fruits and vegetables as well as to purify water. Its consumption induces oxidative stress and activate antioxidant mechanisms such as catalase and heme oxygenase-1 (HO-1) at cellular level. The HO-1 attenuatesthe toxic effectsof metals andROSinvolved inchronic degenerative diseases. Objective: Analyze the effects of Fe++ and bilirubin, products of HO-1 induction by exposure to Colloidal Silver (CS) and its association with oxidative stress parameters Methods: A primary human lymphocytes were exposed to different doses 0.036μg /mL, 0.36μg/ mL and 3.6 μg/mL of colloidal silver and after of 0.5, 2 and 24 hrs, and HO-1 and its productsironand bilirubin were measurement, also protein levelsby colorimetric methods. Data wereanalyzed usingSPSS software, version18,to determinethe association betweenthe parameters Results: TheCS increases HO-1 activity and was associated with bilirubin and iron R=0.518, p=0.0001. Moreover, ironwas associated with proteins levels, r=0.585 p0.0032, hydroxides r=0.390 p0.002, 8 –Iso r= 0.254 p.054, HO-1 r=0.518 p.0001, bilirubin r=.569 p.002 and tend to associate with cell viability r=-0.227 p.082. Also, Fe at theconcentration of 0.036μg/mL and low time exposurepresents association almost with all markers. Conclusion: Colloidal silver at low concentration and times exposure induce HO-1 highly associated with bilirubin and Fe++, which plays an important role when triggering oxidation damage in the membranes,related with citotoxity. These results can be useful tools to study through Fe the OS development in the chronic degenerative diseases, by exposure to xenobiotics such as CS.