Red color in urine of 8-year-old boy may be physiological factors and pathological factors, such as urinary tract infection and acute nephritis. 1. Physiological factors: the little boy may have recently eaten a lot of food rich in red pigment, such as dragon fruit, drinks containing pigment, some snacks with red icing. When the pigment can not be fully metabolized by the body, it will be excreted in the urine, resulting in red urine. 2. Pathologic factors: (1) Urinary tract infection: when the urinary tract is infected, the whole mucosa of the urinary tract is in a congested and edematous state, and ulcers and bleeding can occur locally, so the bladder and urethral mucosa at the site of infection will bleed, producing hematuria. (2) Acute nephritis: the glomerular basement membrane ruptures, and the red blood cells in the blood will be squeezed by the pressure in the blood vessels through the rupture, and discharged from the blood vessels in the kidneys, resulting in a large number of aberrant red blood cells in the patient’s urine. When the urine of an 8-year-old boy is reddish, it is recommended to consult a doctor in time, follow the doctor’s instructions for further examination, and carry out targeted treatment with the help of the doctor.