A toothbrush includes: a hollow head portion defining a first fluid passage therein and having a bristle-mounting wall formed with a plurality of apertures in fluid communication with the first fluid passage; bristle bundles provided on the bristle-mounting wall, each of the bristle bundles being composed of a plurality of hollow bristles, each of the hollow bristles having a third fluid passage that has a connecting end in fluid communication with the first fluid passage and an open free end opposite to the connecting end; a hollow grip portion connected to the head portion and defining a second fluid passage therein, the second fluid passage being in fluid communication with the first fluid passage; and a suction unit connected to the grip portion and adapted to draw a fluid from an exterior of the bristle-mounting wall through the apertures and the third fluid passages.