1.         It is Wajib for the one who hears to say ‘يَرۡحَمُكَ اللّٰه’ (May Allah عَزَّوَجَلَّ have mercy on you) immediately in such an audible voice that the one who sneezed can hear it. (Bahar-e-Shari’at, vol. 16, pp. 119)

2.         Upon hearing ‘يَرۡحَمُكَ اللّٰه’, the person who sneezed should say ‘يَغۡفِرُ اللّٰهُ لَنَا وَلَكُمۡ’ (may Allah عَزَّوَجَلَّ forgive us and you) or say ‘يَهۡدِيۡكُمُ اللّٰهُ وَيُصۡلِحُ بَالَكُمۡ’ (may Allah عَزَّوَجَلَّ guide you and improve your condition).

(Fatawa ‘Aalamgiri, vol. 5, pp. 326)

3.         Whoever says ‘اَلۡحَمۡدُ لِلّٰهِ عَلٰى كُلِّ حَال’ after sneezing and passes his tongue over all his teeth, اِنْ شَــآءَالـلّٰـه عَزَّوَجَلَّ he will be safe from dental diseases.

(Mirat-ul Manajih, vol. 6, pp. 396)

4.         Sayyiduna ‘Ali کَـرَّمَ الـلّٰـهُ تَـعَـالٰی وَجۡـھَـهُ الۡـکَـرِیۡم has said, ‘Whosoever says                       ‘اَلۡحَمۡدُ لِلّٰهِ عَلٰى كُلِّ حَال’ upon sneezing, he will never suffer from pain in the molars or earache.’ (Mirqat-ul Mafatih, vol. 8, pp. 499, Taht-al-Hadees 4739)

5.         The one sneezing should utter ‘اَلۡحَمۡدُ لِلّٰه’ audibly so that it can be heard and answered. (Rad-dul-Muhtar, vol. 9, pp. 684)

6.         The reply [i.e. يَرۡحَمُكَ اللّٰه] is Wajib [necessary] on the first sneeze, if the one sneezing says ‘اَلۡحَمۡدُ لِلّٰه’ on the second sneeze as well, it is not Wajib to reply rather it is Mustahab [desirable]. (Fatawa ‘Aalamgiri, vol. 5, pp. 326)

7.         The reply is Wajib only when the one sneezing says ‘اَلۡحَمۡدُ لِلّٰه’; if he does not say ‘اَلۡحَمۡدُ لِلّٰه’, there is no reply. (Bahar-e-Shari’at, vol. 16, pp. 120)