The main aim of this study was to investigate the oxidative stress, genotoxicity and cytotoxicity of erythromycin (EMC) in pups of treated dams in gestation as well as the lactation period (LP). The two doses of EMC were compared using intraperitoneal (i.p.) route in two different periods, that is, in gestation period and in the LP. The rationale behind selection of i.p. route is because of the fact that EMC gets degrades in acidic pH of the stomach. The doses of EMC used were clinically equivalent dose (CED; EMC 14.2 mg/kg, i.p.) and a lower dose (EMC 10 mg/kg, i.p.) than CED. EMC toxicities in mice pups were evaluated using various parameters such as micronucleus (MN) test in peripheral blood and bone marrow, malondialdehyde (MDA) assay, glutathione (GSH reduced) assay and histopathological assessment in liver tissue. The CED of EMC led to a significant increase in MDA and decreased in GSH concentration in pups' liver tissue in both gestation and LPs and also to a significant increase in MN frequency in both peripheral blood and bone marrow cells of pups. There were no significant toxicities at a lower dose than CED. There were also some chronic findings with liver histopathological examination at CED. It is thus concluded that EMC accentuates the oxidative stress, cytotoxicity and DNA damage in pups of their postnatal life; hence, EMC should be avoided in the pregnancy and also in the LP.