The Prophet (ﷺ) said, If one of you sneezes, let him say:

اَلْحَمْدُ لِلَّهِ

Alhamdu lillaah

All praise is for Allah. [1] After sneezing "Alhamdu lillahi 'ala qulli ha-l". have to be said or at least say "Al-Hamdulillah".

Reference: [1] Bukhari: 6224 [2] Sahih. Tirmidhi: 2741