POMAdd to cart Cankerstop- 100 gr Active ingredient: Ronidazole . Target species: pigeon. Indication: for the treatment of all forms of canker (trichomoniasis) in pigeons. General infections caused by trichomonas. This is a POM – Prescription Only Medicine: it can only be dispensed once a valid prescription issued by a veterinary surgeon is received by email, facebook or attached during the ordering process.