The Messenger of Allah ﷺ forbade these two plants (i.e. garlic and onions), and he said: He who eats them should not come near our mosque. If it is necessary to eat them, make them dead by cooking, that is, onions and garlic. (Using translation from Abū Dāʾūd 3827)
عَنِ النَّبِيِّ ﷺ مَنْ أَكَلَ مِنْ هَاتَيْنِ الشَّجَرَتَيْنِ فَلَا يَقْرَبَنَّ مَسْجِدَنَا فَإِنْ كُنْتُمْ لَا بُدَّ آكِلِيهِمَا فَأَمِيتُوهُمَا طَبْخًا