Total movement distance, mean velocity, and mean distance per movement were partially rescued in fucoidan treatment mice. Fucoidan also protected against the depletion of both striatal dopamine and TH-positive neurons in the substantia nigra pars compacta in the MPTP animal model of Parkinson’s disease. Furthermore, administration of fucoidan effectively limited lipid peroxidation and increased the level/activities of tissue non-enzymic (GSH) and enzymic (SOD, GSH-Px, and catalase) antioxidants of the substantia nigra in MPTP mice. The gene discussed is CAT; the disease is Parkinson disease.