It was narrated from Ma'dan bin Abu Talhah AIYa'muri that 'Umar bin Khattab stood up one Friday delivering a sermon. He praised and glorified Allah, then he said: "0 people, you eat two plants which I do not regard as anything but offensive: This garlic and these onions. At the time of the Messenger of Allah P.B.U.H, I would see a man, if the smell (of these vegetables) was found on him, being taken by the hand and led out to Beqi' (graveyard). Whoever must eat them, let him cook them to death." (Sahih)