Answered by Shaykh Yūsuf Badāt

Question:

Is it permissible to swallow saliva while fasting? Does it break the fast?

Answer:

In the Name of Allāh, Most Merciful, Most Compassionate

Jazāk Allāh Khayr/ Thank you for your question.

Swallowing one’s own saliva will not invalidate the fast. (See: Badā’i al Ṣanā’i)

The act of one deliberately gathering, collecting and swallowing one’s own saliva, to quench thirst, while fasting, is disliked – makrūh – (See: Marāqī al-Falāḥ)

And Allāh Knows Best