When we went through the encyclopedia on the subject of sleeping, we discusses a bit about dream and what happen in the brain at that time. Here is some simple reading on the subject.
Beginning of Creation
Bukhari :: Book 4 :: Volume 54 :: Hadith 513
Narrated Abu Qatada:
The Prophet said, “A good dream is from Allah, and a bad or evil dream is from Satan; so if anyone of you has a bad dream of which he gets afraid, he should spit on his left side and should seek Refuge with Allah from its evil, for then it will not harm him.”
The Book of Vision (Kitab Al-Ruya)
Muslim :: Book 29 : Hadith 5618
Abu Qatada reported Allah’s Messenger (may peace be upon him) as saying: The good vision are from Allah and the evil dreams are from the satan. If one sees a dream which one does not like, one should spit on one’s left side and seek the refuge of Allah from the satan; it will not do one any harm, and one should not disclose it to anyone and if one sees a good vision one should feel pleased but should not disclose it to anyone but whom one loves.
Whenever we are disturbed with a bad dream in our sleep
– upon waking up, spit on your left
– say “audzubillah…”
– do not have to wrry and be scared about it nor tell anyone. Syaitan wants us to be scared so we must fight.
– also remembere to read the quls and ayatul kursi before sleeping and have wudhoo on us too. Insya Allah.