When you sneeze , then say :
Alḥamdulillāh
Your companion should say :
Yarḥamukallāh
When someone says Yarḥamukallāh to you then you should say:
Yahdīkumu ‘llāhu wa yuṣliḥu bālakum.
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.
Reference:
Al-Bukhari 7/125.
