Boy’s penis has a foul smell may be urethritis, local infection, long foreskin, do not pay attention to hygiene and so on. 1. Urethritis: the general clinical manifestations of urethritis are frequent urination, urinary urgency, painful urination, but also urine odor and penis odor. 2. Local infection: men do not pay attention to penile hygiene, underwear is too tight, excessive sweating, etc. may lead to local infection of the penis and local odor, itching and other symptoms. 3. Excessive foreskin: men’s foreskin is easy to hide dirt, infection, if not regularly cleaned, may also lead to penile odor, itching. 4. Not paying attention to hygiene: If men do not pay attention to hygiene in their daily life and do not change their underwear frequently, they may also have penis odor. It may also be caused by other reasons, and it is recommended that the patient go to the hospital in time to clarify the cause of the disease and then treat it.