Bowel diversion surgery allows stool to safely leave the body when (because of disease or injury) the large intestine is removed or needs time to heal. Bowel is a general term for any part of the small or large intestine.
A topical medication is a medication that is applied to a particular place on or in the body, as opposed to systemically.
A buffer solution is one which resists changes in pH when small quantities of an acid or an alkali are added to it. An acidic buffer solution is simply one which has a pH less than 7. Acidic buffer solutions are commonly made from a weak acid and one of its salts - often a sodium salt.