It was narrated from Ma'dam bin Abi Talhah that 'Umar bin Al-Khattab said:
O people, you eat of two plants which I do not think are anything but bad, this onion and garlic. I have seen the Prophet of Allah (ﷺ), if he noticed their smell coming from a man, ordering that he be taken out to Al-Baqi'. Whoever eats them, let him cook them to death.