A new diphenyl-methane derivative is useful to inhibit agglomeration of blood and is defined by the formula, including a diphenylethylene derivative and a benzophenone oxime ether derivative. ##STR1## in which R1 and R2 each are hydrogen, hydroxyl or a lower alkoxy, U is .dbd.CXY or .dbd.N--O--W,X is hydrogen, cyano or --COR6, R6 being hydroxyl or an amino, Y is --R10--COOR3, R3 being hydrogen or a lower alkoxy, R10 being an alkylene having 1 to 3 carbon atoms, straight or branched, --CO--NR4R5, R4 and R5 each being hydrogen, a lower alkyl or a lower arylalkyl, --CH2--NHSO2--C6H5 or --C(R8).dbd.NR7, R7 being a lower alkoxy or an aryl, R8 is --VR9, V being oxygen, sulfur or nitrogen, R9 being an alkyl or an aryl,W is --CH2--CO--CH2--COOR13, R13 being hydrogen or a lower alkyl, --CH2--C(.dbd.NOR14)--CH2--COOR15, R15 being hydrogen or a lower alkyl, R14 being a lower alkyl, --CH(CN)--(CH2)q--COOR16, R16 being hydrogen or a lower alkyl, q being an integer of 1 to 3, or --(CH2)p--Z, Z being --SH, --SCH or a monovalent group derived from a five- or six-membered ring which may be substituted by a ring having one or more sulfur atoms in the ring, p being 1 or 2.