*If one sneezes during the prayer he may say 'Alhamdulilah', except if he is reciting Surah al-Fatihah, for one should recite it completely.
*If one sneezes in the washroom, one should praise Allah (i.e. by saying 'Alhamdulilah') in his heart.
*If one sneezes and you are unsure as to whether he has said 'Alhamdulilah', we should be aware of the following:
a. If you are sure that he has not praised Allah, then you should not say 'Yarham kal-laah', although you may remind him to say 'Alhamdulilah'
b. If you are unsure whether he has said 'Alhamdulilah' but you hear some say 'Yarham kal-laah'. In this case you should say 'Yarham kal-laah' or you can say: 'Yarham kal-laah in konta ha'midtal-laah.' (i.e. May Allah have mercy on you, if you have praised Allah.)
Imam al-Bukhari, may Allah have mercy on him, mentioned this in his book 'al-Adab al-Mofrad' on the authority of Makhool. He said he was sitting beside Ibn Umar () and a man sneezed from the corner of the Masjid, Ibn Umar () said: 'Yarham kal-laah in konta ha'midtal-laah.'
Manners that Relate to Yawning *It is praiseworthy for one to stifle his yawn as much as possible, for yawning is from Satan. The Prophet () said: