Some of the chronic inflammation associated with aging is due to maladaptive responses of the innate immune system to molecular damage, leading to tissue dysfunction and structural changes. Age-related diseases, including neurodegenerative conditions, are fueled by inflammation, with the complement system playing a crucial role in CNS biology and inflammatory processes. Dysregulation of complement activation has been observed in conditions like Alzheimer’s and multiple sclerosis, highlighting its impact on CNS health. Complement’s diverse roles in immunity, tissue homeostasis, and repair make it a key player in both neuroinflammation and neurodegeneration. This overview delves into the sources and functions of complement in normal CNS function, disease pathologies, and potential therapeutic interventions. For more information, please refer to the following link: Link.