What is the meaning of vomiting (al-Qay’) and regurgitation (al-Qals), and what is the detailed ruling for each, mentioning the schools of thought and the most preponderant opinion with evidence, and what is the ruling on the vomit of an animal whose meat is permissible to eat and one whose meat is not permissible to eat?

Vomit is food that exits after settling in the stomach, whereas regurgitation (qalas) is what comes out of the throat but does not fill the mouth; it is less than vomit. The scholarly disagreement regarding the ruling on vomit is the same as the disagreement regarding the ruling on regurgitation. Vomit from non-humans is also impure. As for what a human eats and then vomits: if it was impure before consumption, its impurity increases. If it was pure then exited in an altered state, it is impure by consensus. If it exited unaltered, there is a difference of opinion.