Al-Adab Al-Mufrad, Book 40, Hadith 935 (English) ⓘ

Iyas ibn Salama related that his father said, "A man sneezed in the presence of the Prophet, may Allah bless him and grant him peace, and the Prophet said, 'May Allah have mercy on you.' Then the man sneezed again and the Prophet, may Allah bless him and grant him peace, said, 'This man has a cold.'"

حَدَّثَنَا عَاصِمُ بْنُ عَلِيٍّ، قَالَ‏:‏ حَدَّثَنَا عِكْرِمَةُ، قَالَ‏:‏ حَدَّثَنَا إِيَاسُ بْنُ سَلَمَةَ، عَنْ أَبِيهِ قَالَ‏:‏ عَطَسَ رَجُلٌ عِنْدَ النَّبِيِّ صلى الله عليه وسلم فَقَالَ‏:‏ يَرْحَمُكَ اللَّهُ، ثُمَّ عَطَسَ أُخْرَى، فَقَالَ النَّبِيُّ صلى الله عليه وسلم‏:‏ هَذَا مَزْكُومٌ‏.‏