A designed nontoxic, nonhemolytiC 11-residue peptide, NF11 (NAVRWSLMRPF), not only inhibits the aggregation of amyloid beta (A beta 40) protein but also,disaggregates the preformed oligomers and mature A beta fibrils, thereby reducing associated-toxicity. NMR experiments provide evidence of NF11's ability to inhibit fibril formation, primarily through interaction with the N-terminus region as well as the central hydrophobic cluster of A beta 40. NF11 has micromolar binding affinity toward both monomeric and aggregated species for efficient clearance of toxic aggregates. From these in vitro results, the future development of a next generation peptidomimetic therapeutic agent for amyloid disease may be possible.