Alhamdulillah when sneezing
إِنَّ اللَّهَ يُحِبُّ الْعُطَاسَ وَيَكْرَهُ التَّثَاؤُبَ، فَإِذَا عَطَسَ أَحَدُكُمْ وَحَمِدَ اللَّهَ كَانَ حَقًّا عَلَى كُلِّ مُسْلِمٍ سَمِعَهُ أَنْ يَقُولَ لَهُ: يَرْحَمُكَ اللَّهُ
Inna-llaha yuhibbu-l-utas wa yakrahu-t-tatha'ub, fa-idha 'atasa ahadukum wa hamida-llaha kana haqqan ala kulli muslimin sami'ahu an yaqula lahu: Yarhamuka-llah.
"Allah loves sneezing and dislikes yawning. When one of you sneezes and praises Allah, it is a right upon every Muslim who hears him to say: Yarhamuk-Allah (may Allah have mercy on you)."
Narrated by Abu Hurayrah. Sahih al-Bukhari 6226
A short reflection
A small reflex turned into a chain of remembrance. Sneeze, praise. Hear, bless. Reply: Yahdikum-ullahu wa yuslihu balakum.