Corrosion resistance of SS18/8 alloy, SS316L alloy, Gold18carat and Gold 22 carat in artificial saliva in the absence and presence of Erythromycin tablet 500mg has been evaluated by electrochemical study such as polarization study. For SS316L alloy, Gold 18 carat and Gold 22 carat, Polarization study leads to the conclusion that corrosion resistance of SS316L alloy, Gold 18 carat and Gold 22 carat decreases in the order : AS + Erythromycin > AS. Hence, people clipped with an orthodontic wire made of SS316 alloy, Gold 18 carat and Gold 22 carat can take Erythromycin tablet orally without any hesitation. For SS18/8 alloy, polarization study leads to the conclusion that corrosion resistance of SS18/8 alloy decreases in the order: AS > AS + Erythromycin. So, people clipped with an orthodontic wire made of SS18/8, should avoid taking Erythromycin tablet orally.