The amyloid beta-peptide (A beta peptide) is assumed to play a crucial and early role in the pathogenesis of Alzheimer disease. Thus, strategies for a pharmacotherapy aim at reducing A beta peptide generation, which proteolytically derives from the amyloid precursor protein (APP). The main targets so far have been beta- and gamma-secretase, the two proteases that cleave APP at the N- and C-terminus of the A beta peptide and are thus directly responsible for A beta peptide generation. A different strategy, namely the activation of alpha-secretase, has barely been investigated for its therapeutic potential. alpha-Secretase cleaves within the A beta peptide domain and thus precludes A beta peptide generation. Now, new results demonstrate that activation of alpha-secretase indeed reduces A beta peptide generation and toxicity in vivo.