Placebo-controlled, randomized, double-blinded clinical study that included twenty cats (ten experimental and ten control) challenged with feline rhinotracheitis virus showed efficacy of Polyprenyl Immunostimulant. All cats enrolled in the study tolerated the administration well, no adverse events occurred. No toxicity was observed with the substance administered orally twice daily at 0.5 mg/kg for 15 days.

All cats in the study developed signs of rhinotracheitis at some time of the experiment. Severity of the disease was scored daily, and the scores were summarized for each cat and each group for the period 21 days post-challenge. Our results showed that oral administration of Polyprenyl Immunostimulant reduced duration and severity of rhinotracheitis in the cats infected with feline rhinotracheitis virus. Polyprenyl Immunostimulant reduced severity and duration of rhinitis and reduced severity of conjunctivitis in cats infected with feline rhinotracheitis virus.