What are the pillars of fasting?
The pillars of fasting are intention and abstaining from all nullifiers of fasting from dawn to sunset.
Does the use of suppositories, enemas, or hemorrhoid creams affect the validity of fasting?
Enemas and suppositories inserted through either of the two private passages invalidate the fast. This ruling is based on the statement of Ibn Abbas (may Allah be pleased with him): "Breaking the fast occurs from what enters (the body), not from what exits." [Reported by Al-Bayhaqi in As-Sunan Al-Kubra]
His generalization regarding anything entering the body indicates that it invalidates fasting, whether it is nutritious or not, as even non-nutritious substances resemble food in form.
It is recommended to use them before Fajr or after Iftar. However, if a person must use them while fasting, they should continue refraining from food and drink for the rest of the day and make up for that day later.
Does collecting saliva and swallowing it break the fast?
Swallowing collected saliva does not break the fast, but it is an unnecessary and meaningless act.
What is the ruling on a vowed animal sacrifice?
A vowed animal sacrifice is to be distributed amongst the poor and needy, and neither the vow-maker, nor those supported by him are to eat from it.