The Feline Tritrichomonas Project Better outcomes for cats
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An Oriental Shorthair cat photographed close, looking at the camera
Photo: Felinlove · CC BY-SA 4.0 · Wikimedia Commons
Tritrichomonas foetus · Tritrichomonas blagburni

The short version

Everything on this site, cut down to what a person actually needs to hold in their head. No jargon, no tables, no citations on this page — the evidence behind each line is on the longer pages, and every one of them is linked at the foot of this summary.

Same facts, plainer words Reviewer of record: pending Last verified 28 Oct 2026

In seven sentences

  • A tiny one-celled creature lives in the last part of a cat’s gut. Its name is Tritrichomonas.
  • It causes runny poo that smells very bad and does not go away. Some cats carry it and look completely fine.
  • The ordinary poo test misses it most of the time, because it looks like another bug down the microscope.
  • There is a better test that looks for its DNA. Ask your vet for that test, and ask them to take the sample with a small loop instead of a flush.
  • Most cats get better with a medicine called ronidazole. About one cat in four needs a second course.
  • Scoop the litter tray every day. Keep a cat that has not been re-tested away from cats that were never infected.
  • If you think your cat has this, say so out loud to your vet. A test that came back normal does not rule it out.

Where each of those lines comes from

Nothing above is a simplification in the sense of being looser than the evidence. It is the same material, written shorter.

  • What it is — the organism, where it lives, and what it does to the gut wall.
  • Diagnosis — why a fecal smear misses it, and which test to ask for.
  • Treatment — ronidazole, the dosing history, and what to watch for.
  • For owners — the sequence of decisions, from first symptom to clearance.
  • For rescues and for catteries — what changes when there are many cats.
  • Research — every claim, with its PubMed record.
One thing worth saying plainly This page is a summary, not a diagnosis, and it is not a dosing sheet. Doses and drug decisions belong to a veterinarian who has seen your cat — and a negative test never rules this infection out on its own.