Upon sneezing1 du'a

When you sneeze, then say: All praises and thanks are to Allah. Your companion should say: May Allah...

Reference:Al-Bukhari 7/125.Hisnul Muslim 188

(الْحَمْدُ لِلَّهِ) (يَرْحَمُكَ اللَّهُ) (يَهْدِيكُمُ اللَّهُ وَيُصْلِحُ بَالَكُمْ)

Transliteration

When you sneeze, say: AlḥamdulillāhYour companion should say: YarḥamukallāhWhen someone says Yarḥamukallāh to you then you should say: Yahdīkumu ‘llāhu wa yuṣliḥu bālakum.

Translation

When you sneeze, then say: All praises and thanks are to Allah. Your companion should say: May Allah have mercy upon you. When someone says Yarḥamukallāh to you then you should say: May Allah guide you and set your affairs in order.