Is it permissible to give one-fifth of the Sadaqah to the Prophet's Household (Ahl al-Bayt)?

What you heard about the permissibility of giving one-fifth of charity to the Prophet's household (Ahl al-Bayt) is incorrect if what is meant is zakat, for zakat is not permissible for Ahl al-Bayt. This is based on the Prophet's (peace be upon him) saying: "Do you not know that we do not eat from charity?" And his saying: "Indeed, charity is not permissible for us." And there is a consensus on this matter.

As for voluntary charity (sadaqat al-tatawwu'), there is a well-known difference of opinion, and what is forbidden for them is zakat, not voluntary charity. As for the one-fifth (khums) that is given to Ahl al-Bayt, it is the share of close relatives from the one-fifth of spoils of war (ghanima) and Fay' (revenue from conquered lands), based on Allah's saying: "And know that whatever you gain of war booty, that indeed, for Allah is one fifth of it and for the Messenger and for [his] near relatives and the orphans, the needy, and the [stranded] traveler." (Qur’an 8:41) And based on His saying: "Whatever Allah has returned to His Messenger from the people of the towns - it is for Allah and for the Messenger and for [his] near relatives and the orphans, the needy, and the [stranded] traveler." (Qur’an 59:7)