Introduction: Streptomyces manage the osmotic stress by collecting compatible solutes or osmolytes. Ectoine, 1,4,5,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid, and 5-hydroxyectoine are among the most common osmolytes of this bacteria and have an active role in protecting the genetic material of this microorganism as well as providing resistance to environmental pressures. In this research, the antiproliferative and apoptotic effects of ectoine and 5hydroxyectoine on human non-small cell lung cancer (NSCLC) cell line (QU-DB) are investigated. Methods: QU-DB cells were treated by five doses of ectoine and hydroxyectoine for 12, 24 and 48 hours, and the cytotoxic properties were evaluated by MTT assay. Then, the DAPI fluorescent staining was carried out for monitoring of the cells' nuclear morphology. Recognition and quantification of the apoptosis were done; using the Annexin-V-Fluos technique. Results: It has been verified that both ectoine and hydroxyectoine persuaded apoptosis on QU-DB cells in a dose-dependently manner. Also, no cytotoxicity effects of these compatible solutes were observed on normal cells (HFLF-PI5). Conclusions: Ectoine and hydroxyectoine are two natural metabolites which induce apoptosis in lung cancer cells. They don't have any toxic effect on normal cells and can be used as auxiliary drugs or even as a medicine for the treatment of lung cancer after further optimization of the formulations.