From Sahih Muslim (Hadith 5901):
Abu Salama reported:I used to see dreams, but the hadith transmitted on the authority of Laith b. Nu`man, the words of Abu Salama at the concluding part of the hadith are not mentioned. Ibn Rumh has reported in the hadith: "He (one who sleeps) should change the side on which he had been lying before
Reference: Muslim 5901