Background: Reducing the burden of beta-amyloid accumulation and toxic autoimmunity-related proteins, one of the recognized pathophysiological markers of chronic and common neurological disorders such as Alzheimer’s disease (AD) and multiple sclerosis (MS), may be a valid alternative therapy to reduce their accumulation in the brain and thus reduce the progression of these disorders. The objective of this review was to evaluate the efficacy of plasmapheresis (PP) in AD and chronic progressive MS patients (in terms of improving clinical symptoms) and to analyze its safety and protocols. Methods: Articles related to this topic and published without time limitations in the Medline, and Cochrane databases were reviewed. Results: In AD patients, PP reduced amyloid beta (Aβ) levels in the brain, accompanied by a tendency towards cognitive stabilization, and improved language and verbal fluency. In regards to structural and functional brain changes, PP reduced brain volume and favored the stabilization, or absence, of the progression of perfusion. In chronic progressive form of MS patients, PP improved neurological deficits in 20–70% of patients with a chronic progressive form of MS, and restored interferon (IFN) responsiveness, which was not accompanied by any image change in brain plaques. Conclusions: Therapeutic plasmapheresis with albumin replacement is a promising strategy for reducing Aβ mediated toxicity and slowing the progression of the disorder. Some patients with chronic progressive forms of MS show improvement in neurological deficits. The features of AD and MS patients who benefit most from this approach need further research.