Canker is not a disease, it is a single-celled Flagellate parasite. Adult pigeons usually carry the parasite without displaying any symptoms. Young birds can suffer severe, sometimes fatal Canker. Young birds are typically infected orally by their parents. Canker may be found in saliva and droppings and may also be transmitted in the drinking water Symptoms may include a whitish, cheesy form in the throat or other cavity. Treatment is individual or through the drinking water. It is advisable to alternate products to prevent a resistance. The whole flock should be treated. A product that gives protection of the liver should follow treatment as well as vitamins and probiotics. Preventative treatment is 3-5 days before the breeding season. Regular prevention may be considered every month or so. Sometimes Canker is confused with Sinusitis. Sinusitis is a yellowish, stringy substance removed with a Q-Tip or toothpick and will not bleed. This is best treated with Doxyty or Tylan 200. In any Canker-control program, rotate at least two medications in order to decrease the possibility of developing a resistance. Rotate every 3 or 4 treatments.