"Dreams are from Allah and Hulum are from Shaitan. So when one of you sees something that bothers him, then let him spit on his left three times, and let him seek refuge in Allah from its evil. Then it will not harm him."  

عَنْ رَسُولِ اللَّهِ ﷺ أَنَّهُ قَالَ الرُّؤْيَا مِنَ اللَّهِ وَالْحُلْمُ مِنَ الشَّيْطَانِ فَإِذَا رَأَى أَحَدُكُمْ شَيْئًا يَكْرَهُهُ فَلْيَنْفُثْ عَنْ يَسَارِهِ ثَلاَثَ مَرَّاتٍ وَلْيَسْتَعِذْ بِاللَّهِ مِنْ شَرِّهَا فَإِنَّهَا لاَ تَضُرُّهُ قَالَ وَفِي الْبَابِ عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو وَأَبِي سَعِيدٍ وَجَابِرٍ وَأَنَسٍ قَالَ وَهَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ