General anesthesia (GA) is a widely used medical intervention, given to patients to eliminate pain during invasive procedures and surgeries, effectively revolutionizing the field of medicine. GA induces a reversible unconscious state by potentiating inhibitory receptors like GABA (γ-aminobutyric acid) receptors. Despite the practical uses of GA, recent studies have raised concerns about the potential risks associated with anesthesia exposure on the brain and cognitive function. In recent studies, these adverse effects, like neuronal death, can cause neurotoxicity despite the reversible and transitory nature of most GAs. In this paper, we discuss the neurological and behavioral outcomes after GA in developing and post-developed brains. These findings highlight serious concern on how GA impacts neurocognition and brain activity in both immature and mature brains and the potential harmful long term effects of GA. By understanding anesthetic-induced neurotoxicity, more avenues can be explored to particularly learn how to effectively protect vulnerable populations from harmful effects to the brain and warrant further research on clinical applications of anesthesia.