Prostatic hyperplasia is an enlargement of the prostate gland that occurs most often in middle-aged and old dogs. Benign prostatic hyperplasia may cause constipation, painful urination, and weight loss. The best treatment for benign prostatic hyperplasia is castration (neutering).

The prostate gland produces fluid that helps transport and nourish sperm. In older males the prostate gland tends to enlarge and become painful. This enlargement tends to press against the rectum and urethra , impairing bowel function and causing urinary tract problems.