Answered by Shaykh Faraz Rabbani
Just want to know the permissibility of using standard toothpaste whilst fasting, is it permissible? I have been told by our local Imam that this is permissible.
Answer:
Walaikum assalam,
In itself it is permissible to use toothpaste while fasting. However, if even a little of the actual toothpaste goes down your throat, even if indirectly by affecting the saliva, it would invalidate the fast.
One should therefore avoid using toothpaste while fasting and if forced to should use only a very small amount, and brush in such a way that one rids one’s mouth of all traces of toothpaste with reasonable surety.
Wassalam,
Faraz