The World Federation One Stop Fiqh

Ruling 1640

If a fasting person burps and something comes up in his mouth, then based on obligatory precaution, if he intentionally swallows it his fast is invalid and he must keep a qaḍāʾ fast and give kaffārah. And if eating that thing is unlawful – for example, when burping, blood or some food-like substance that has lost the form of food reaches his mouth and he intentionally swallows it – it is better that he gives the ‘total kaffārah’ [as defined in Ruling 1635].