‘A'isha said that Hamza b. ‘Amr al-Aslami who was greatly devoted to fasting asked the Prophet whether he should fast when on a journey, and received the reply, “Fast if you like, or break your fast if you like.”
‘Ata’ said, “If one rinses his mouth and ejects the water in it, swallowing his saliva and anything that remains in it does him no harm; but one should not chew gum, for although I do not say that he breaks his fast he swallows the saliva produced by the gum, he is nevertheless prohibited from doing it.”
Abu Sa'id al-Khudri said that when they went out on an expedition with God’s messenger on the sixteenth of Ramadan some fasted and some broke their fast, but neither party found fault with the other.
Bukhari said without a complete isnad that Ibn ‘Umar used to have himself cupped whan he was fasting. Then he abandoned it and had himself cupped at night.