The results of physiological and immunological studies of rat pups born from females who were exposed to passive smoking and exposure to tetrapeptide KK1 during pregnancy are presented. From the 1st to the 21st postnatal days, the somatic and sensorimotor development of offspring was studied using a set of tests developed at the P.K. Anokhin Institute of Normal Physiology. The level of cytokines IFN gamma and IL-6 produced by rat splenocytes was studied in culture fluid by the ELISA method. In baby rats born from passively smoking females, compared with animals born from non-smoking rats, a decrease in the weight of baby rats was found, as well as a delay in the timeliness of somatic and sensorimotor development. The introduction of the peptide KK 1 non-smoking females increases the index of timeliness of somatic and sensorimotor development.
 The results obtained show an induced variant of secondary immunodeficiency in baby rats born from passively smoking rats during pregnancy. Administration of the KK1 peptide to non-smoking rats did not change the immunological parameters of the baby rats. On the contrary, the production of peptide KK1 by pregnant rats who smoked was accompanied by changes in the number of cells in lymphoid organs and the production of cytokines by splenocytes in the born rats.