A bicyclic cinnamide compound represented by the general formula (I): wherein ---- represents a single bond or a double bond; Ar 1 represents a phenyl group or pyridinyl group optionally substituted by one to three substituents; R 1 and R 2 each represents a C1-6 alkyl group, a hydroxyl group, etc.; Z 1 represents an optionally substituted methylene group or vinylene group, an oxygen atom, or an imino group optionally substituted by a Cl-6 alkyl group or a Cl-6 acyl group; and p, q, and r each is an integer of 0 to 2. It functions to reduce A²40 and A²42. It is hence useful especially as a prevention or remedy for neurodegenerative diseases of which A² is causative, such as Alzheimer's disease and Down's syndrome.本發明關於新穎的二環肉桂醯胺化合物,及包含此化合物作為活性成分的藥劑。由通式(I)所代表的二環肉桂醯胺化合物: (I);其中 代表單鍵或雙鍵;Ar1代表可由1至3個取代基所取代之苯基或吡啶基;R1及R2各自代表C1-6烷基,羥基,或類似基團;Z1代表可由1或2個選自於取代基組群A1之取代基所取代的亞甲基或亞乙烯基,氧原子,或可由選自於取代基組群A1之取代基所取代的亞胺基;以及p、q及r各自代表整數0至2,其具有降低Aβ40及Aβ42產生的功效,以及因此特別有用於作為因Aβ所引起的神經退化性疾病,例如阿茲海默症(Alzheimer's disease)或唐氏症候群(Down's syndrome)的預防或治療藥劑。