Dementia is treated by administering a composition that includes an omentum tissue or an aqueous or organic extract of the omentum tissue to a mammal in need of treatment of dementia. The composition can be administered to the mammal via oral administration, parenteral administration, inhalation, topical administration, rectal administration, vaginal administration, implantation, or any combinations thereof. The mammal can also be treated by stimulating a tissue that includes omentum.
