Abstract: Disclosed is a pharmaceutical composition containing a compound useful for inhibiting neurotoxicity caused by beta amyloid. The pharmaceutical composition of the present disclosure contains 1,3,5,7-tetrakis(aminomethyl)adamantane, an analogous compound thereof or a salt thereof as an active ingredient. The inventors have studied methods for reducing the toxicity of beta amyloid oligomers based on the formation mechanism of dodecamers in consideration of the fact that especially the dodecamers from among the beta amyloid oligomers exhibit a significant activity as a toxin for synapses and neurons in cranial nerve diseases. The inventors have confirmed that the disclosed compound can induce structural epitope deformation of the dodecamer and thereby reduce toxicity of the beta amyloid oligomers.