Does swallowing saliva or phlegm invalidate the fast?

Question : This is a female questioner, Honorable Shaykh Muhammad, who says: If a person fasting complains of excessive production of saliva or phlegm during fasting, and some of it enters his stomach, does that invalidate the fast?

Answer : Praise be to Allah, Lord of the worlds, and I send prayers and peace upon our Prophet Muhammad, and upon his family and his Companions, and upon those who follow them in excellence until the Day of Judgment. Excessive saliva and excessive phlegm do not affect the person fasting. That is because it is beyond his control. If he swallows some of the saliva, it does not invalidate his fast. Rather, a person spits it out and expels it, whether he is fasting or not. In summary, swallowing saliva does not have an effect, even if it is excessive.