If the penis erection occurs occasionally when bathing, there is generally no obvious harm; but if it is frequent, it may cause certain harm, such as inducing prostatitis, reproductive dysfunction and so on. As the male penis is stimulated by the flow of water during bathing, the blood-filled penile corpus cavernosum will hold up the penis, which is generally a normal physiological reaction, and occasional occurrences generally do not have obvious harm. But if frequent penile erection may be certain harm, repeated erection may lead to male genital gland area congestion, long-term easy to induce prostatitis. It can also cause damage to the cavernous cells of the penis in male patients, leading to the emergence of reproductive dysfunction, thus causing a decline in sexual function. It is recommended that patients try to control the water flow when bathing, do not turn on too much, if there is discomfort timely consultation.