The anti‐trichomonal efficacy and pharmacokinetics of dimetridazole were investigated in the homing pigeon(Columba livia). Dimetridazole was formulated for drinking water medication and as a prolonged‐release tablet. To suppress aTrichomonas gallinaeinfection successfully, medicated drinking water containing dimetridazole (400 mg/L) had to be administered for at least 3 days. A two‐day treatment with a dimetridazole tablet (20 mg/tablet) in fasted, as well as in fed, pigeons was shown to be ineffective. After intravenous administration of 20 mg dimetridazole, the drug plasma concentration‐time profile fitted a one‐compartment open model with a mean half‐life of 3.9 h. The absolute bioavailability of the tablet in fasted pigeons was 83.8%. The bioavailability of the tablet administered with food was reduced by 20%. Dimetridazole was rapidly metabolised to (1‐methyl‐5‐nitroimida