In addition to causing difficulty in urination, prostate enlargement can sometimes cause hematuria because the enlarged prostate can cause congestion in the urethral prostate and bladder mucosa and expansion of the small veins. In order to overcome the urethral obstruction caused by prostate enlargement and to urinate, the patient will force or even hold his breath to increase the abdominal pressure to expel the urine. The pressure in the small blood vessels in the mucosa of the bladder wall also rises sharply during the forceful breath-holding process, which can lead to microscopic hematuria or hematuria in the naked eye if the vessels rupture. Small bleeding often stops on its own, and occasionally large amounts of hematuria and large clots fill the bladder, making it more difficult to urinate, or even retain urine, when bladder outlet obstruction has already occurred. In addition, patients with prostate enlargement undergoing cystoscopy, metal catheter catheterization, or sudden bladder decompression during catheterization for acute urinary retention are prone to severe hematuria. Prostatic hyperplasia complicated by hematuria is one of the common causes of hematuria in elderly men and should be differentiated from urological tumor hematuria.