It is reported from Abu Hurayra [Radhiallaahu anhu[ from Nabi [Sallallaahu Alayhi Wasallam] he said, ?Allah certainly, loves sneezing and dislikes yawning.?
When a person sneezes and praises Allah, it is a right upon every Muslim who hears him that he replies to him and as for yawning, it is from Shaytaan. So, he should try to stop yawning to the best of his ability. When a person’s yawn results in a sound ?haa?, Shaytaan laughs at him. (Bukhari vol.2 pg.919; Qadeemi)
It is reported from Abu Hurayra [Radhiallaahu anhu] from Nabi [Sallallaahu Alayhi Wasallam] that he said, ?When one of you sneezes, he should say, ?Alhamdulillah? and his brother of his companion should reply to him ?Yarhamukallaah?. When this person says ?Yarhamukallaah?, he should say, ?Yahdeekumullaah wa yus-lih baalakum?.. (Bukhari vol.2 pg.919; Qadeemi)
A Hadith in Sahih Muslim mentions, ?When a person yawns, he should block his mouth with his hand as Shaytaan enters, i.e. the mouth.? (Sahih Muslim vol.2 pg.413; Rashidiyyah)
We are unaware of any du’aa to be read after yawning. (Imdaadul Fataawa vol.4 pg.35)
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai