Praise be to Allaah.
Eating qat is haraam, because it makes people listless and
distracts them from remembering Allaah and from praying. It is not
permissible to delay the prayer from its proper time or to fail to pray in
congregation. These are evil actions which result from eating qat, and
they are all haraam actions. Hence eating qat is emphatically forbidden.
And Allaah is the Source of strength. May Allaah send
blessings and peace upon our Prophet Muhammad and upon his family and
companions.
From Fataawa al-Lajnah al-Daa’imah, 22/175.