'Aaishah (radhi-yAllaahu 'anhaa) related that The Prophet (sal-Allaahu 'alayhe wa sallam) [during his illness in which he passed away] would dip his hands in water and then he would wipe his face and say:

لاَ إِلَهَ إِلاَّ اللَّهُ إِنَّ لِلْمَوْتِ سَكَرَاتٍ

There is none worthy of worship but Allah, surely death has agonies.

Laa 'ilaaha 'illallaahu 'inna lilmawti lasakaraatin.

Al-Bukhari, cf. Al-Asqalani, Fathul-Bari 8/144. The Hadith also mention him using the Siwak (tooth stick).