The sudden spontaneous healing of simple urinary occult blood is mainly related to the cause of the blood in the urine. Common causes include strenuous exercise, minor urinary tract infections, and stones. 1. strenuous exercise: normal people who usually exercise less, after suddenly increasing the amount of exercise may appear exercise hematuria, manifested as simple urinary occult blood, but this is only transient, after resting can be self-negative, so there may be a sudden spontaneous healing. 2. Mild urinary tract infection: the symptoms are mild, there may be transient or short-term hematuria, manifested as simple occult blood in urine, when the patient’s own immunity to improve or drink more water, urinate diligently and other lifestyle improvements, there may also be a sudden spontaneous healing. 3. Urinary stones: Urinary stones can lead to the emergence of simple occult blood in the urine, if the stones are small particles, can be excreted through the urethra with urination, so there can be occult blood in the urine suddenly self-cure. Simple urinary occult blood may also have other reasons, it is recommended to go to the regular hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.