[fuzzball]

After 3 days of not eating or pooping we took our 9 month old ragdoll kitten to the vet. She seemed happy and normal, was grooming, drinking and peeing but of course we were concerned because she's a piglet who adrores her food.
They gave her an x-ray to check for any foreign bodies/blockages (none, but she was chock full of poop) but they told us it wouldn't show things like hair elastics, string, tinsel etc that kittens her age like to nibble on.
They also gave her an enema. The enema only retreived 4" of poop, they told us to expect another 6" soon.
We were also told we could give her hairball control paste (aka kitty malt/beef flavoured mineral oil) 3 times a day to get things moving. We smeared a 1/4 teaspoon on top of each foot so she had to lick it off.
Also after vomiting one meal she attempted on day 4, she didn't want to drink anymore, so we took a syringe (no needle of course) and squirted water into her mouth regularly since hydration helps pooping.
On day 5 she finally pooped those 6" out and wanted her breakfast.
There was nothing foreign in her poop at all since the vet told me to check for carpet strings, etc so we would have a better idea what caused this. It was just constipation, but once there is no room in the colon for any more, they can't keep their food down or want any more.
In future we were told to supplement her diet with a little kittymalt once each day 1/2 teaspoon, and put out pumpkin to help her along with fibre. We plan to flavour the pumpkin with the juice from her wet food tin, which is what we feed her 3 times a day plus at night some dental kibble to snack on for her teeth.
Hope this helps you, too.