This study investigates both separate and joint (ASA+ AcH) effects of acetylsalicylic acid (ASA), an active ingredient of aspirin, and acetaldehyde (AcH), an intermediary metabolite in alcohol metabolism, on some developmental features of Drosophila melanogaster. Substances were applied to Drosophila melanogaster by means of nutrition, adding them to culture media. With the effects of ASA and AcH, egg fertility decreased in the F-1 generation, while it increased in the F-2 generation. This increase was even more evident in the experimental groups of F-2 that were influenced by ASA and AcH together. Egg development was inhibited in experimental groups exposed to low concentrations of AcH. However, at high ASA+AcH concentrations (ASA + 20 mM AcH, ASA + 30 mM AcH), egg development was close to or higher than that of the control group. The number of larvae in the culture medium containing AcH and ASA decreased in the F-1 generation, while it increased in the F-2 generation. This increase was more evident with the combination of ASA and AcH. It can be concluded that the combination of ASA and AcH resulted in the development of resistance to those substances.