Bathing problems

My mother has a shih-poo, male puppy who for the last 6mths (he's one) decided he doesn't like to take a bath. So much so, he becomes aggressive and has drawn blood on a few occassion. Unfortunately my mother is now afraid of the little monster. Is there anyway to get this whole process pleasurable for him? She wants to invest in a muzzle but there must be another way! Ordinarily he's sweet but when he sees the towels coming he runs to hide and turn into a monster.

Any suggestions?