JAMI AL-TIRMIDHI

Leftover of dog
  (91)

Sayyidina Abu Huraira (RA) reported that the Prophet (SAW) said, "When a dog laps a
vessel wash it seven times, rubbing it with earth the first or the last time. If a cat puts its
mouth into a vessel wash it once."

[Ahmed9516, 9936, Bukhari 172, Muslim 279, Abu Dawud  71, 72, Nisai  83, Muslim 364]