The invention relates to a damper (1, 1′) for furniture, especially hinges, comprising a housing (2, 2′) in which a piston (8, 8′) is connected to a piston rod (3, 3′) and can be displaced. A fluid flows through at least one flow channel (11, 11′) on or in the piston (8, 8′) during a movement of the piston (8, 8′) inside the housing (2, 2′), the movement of the piston (8, 8′) resulting in a different damping power in different directions. The cross-section of the flow channel can be modified in some sections on at least one groove (20, 20′) by moving a plate (12, 12′) relative to the piston (8, 8′). On the at least one groove (20, 20′), a substantially funnel-shaped outlet (22, 22′) and/or the groove (20′) have a section which is arranged at an angle to the radial direction to avoid cavitation.