Say Alhamdulillah when you sneeze

عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ إِذَا عَطَسَ أَحَدُكُمْ فَلْيَقُلِ الْحَمْدُ لِلَّهِ‏.‏ وَلْيَقُلْ لَهُ أَخُوهُ أَوْ صَاحِبُهُ يَرْحَمُكَ اللَّهُ‏.‏ فَإِذَا قَالَ لَهُ يَرْحَمُكَ اللَّهُ‏.‏ فَلْيَقُلْ يَهْدِيكُمُ اللَّهُ وَيُصْلِحُ بَالَكُمْ ‏"‏‏.

“The Prophet ﷺ said, " If anyone of you sneezes, he should say 'Al-Hamduli l-lah' (Praise be to Allah), and his (Muslim) brother or companion should say to him, 'Yar-hamuka-l-lah' (May Allah bestow his Mercy on you). When the latter says 'Yar-hamuka-llah", the former should say, 'Yahdikumul-lah wa Yuslih balakum' (May Allah give you guidance and improve your condition)”

قَالَ عَطَسَ رَجُلاَنِ عِنْدَ النَّبِيِّ صلى الله عليه وسلم فَشَمَّتَ أَحَدَهُمَا وَلَمْ يُشَمِّتِ الآخَرَ، فَقِيلَ لَهُ فَقَالَ ‏ "‏ هَذَا حَمِدَ اللَّهَ، وَهَذَا لَمْ يَحْمَدِ اللَّهَ ‏"‏‏.

“Two men sneezed before the Prophet. The Prophet ﷺ said to one of them, "May Allah bestow His Mercy on you," but he did not say that to the other. On being asked (why), the Prophet ﷺ said, "That one praised Allah (at the time of sneezing), while the other did not praise Allah”