Effectiveness of Cranberry Supplementation for Prevention and Treatment of Infectious Urinary Tract Disease in Dogs and Cats: A Systematic Review.

Cranberry and cranberry extracts are available for treatment or prevention of urinary tract disease in dogs and cats, but guidance regarding their use is lacking. The objectives were to identify and assess literature pertaining to the efficacy of cranberry and cranberry extract supplementation for prevention and treatment of bacterial cystitis and subclinical bacteriuria in dogs and cats. A systematic review was performed, and three studies involving a total of 122 animals (106 dogs and 16 cats) were identified. No studies reported statistically significant or numerical impacts of treatment. Two studies were deemed at high risk of bias, and one was deemed at low risk. Certainty of evidence was low to very low. The small number of studies, small sample sizes, data from those studies, and low certainty of evidence preclude confident assessment of the role of cranberry for the prevention or treatment of infectious urinary tract disease in dogs and cats.