My breath smells like poop. my dentist & hygienist says my mouth/teeth/gums are in perfect shape. i brush/floss/tongue scrape/mouthwash rinse 4 times a day. i have not been drinking a lot of water which has me constipated, can that be the cause?

Bad breath can be caused by many different factors, including sinus infections, periodontal problems, smoking, cavities, acid reflux, and your diet. Since your mouth is in perfect shape it's something else. Address all of these possibilities with your physician, and I'm confident that your problem will at least be minimized, and hopefully eradicated.

You need to hydrate your body with water and flush out all the useless waste products. Not drinking a lot of water leads to a dry mouth and a build up of bacteria that can cause a bad smell. Your oral hygiene is good and your diet normal, than a dry mouth is your cause of bad smell, start drinking water and drink before going to bed.