The Grand Ayatollah Makarem Shirazi answered a question about the duty of a person who is fasting when sputum enters his mouth whilst performing Salaat.
Question: What is the duty of a person who is fasting and performing Salaat when sputum enters his/her mouth?
The Grand Ayatollah Makarem: When sputum enters the mouth of a person who is fasting and performing Salaat, he/she must get rid of it and if it was not possible, cut the Salaat (of course can change the intention from Wajeb Salaat to Mostahab Salaat and leave the Salaat) and then after getting rid of sputum, perform the Salaat again.
source : Shafaqna
