Dua When Sneezing
الْحَمْدُ لِلَّهِ
Alhamdulillah.
"All praise is due to Allah."
Sahih Al-Bukhari 6224
Spiritual Benefits
Sneezing clears the mind and body. Thanking Allah acknowledges this physical blessing.
When Should I Say This Dua?
Say this immediately after sneezing.
Proper Etiquette (Sunnah)
If someone hears you, they should reply 'Yarhamukallah' (May Allah have mercy on you), to which you reply 'Yahdikumullahu wa yuslihu balakum' (May Allah guide you and rectify your condition).