ABSTRACT This invention relates to methods of treating Alzheimer's diseaseor symptoms thereof, and amnesic mild cognitive impairment or symptoms thereof.Methods of the invention include administering a therapeutically effectiveamount of tissue kallikrein, variants or active fragments thereof. The inventionfurther relates to uses of tissue kallikrein or a variant or active fragment thereoffor the digesting or cleaving amyloid and the treatment of conditions benefitingfrom the digestion or cleavage of amyloid. The invention further relates to pharmaceuticalcompositions comprising a therapeutically effective amount of tissue kallikrein,variants or active fragments thereof formulated for oral or intranasal administration.