Redness and swelling of the urethra after circumcision is usually caused by inflammation, drinking too little water and poor blood return. 1. Inflammation: redness and swelling of the urethra after circumcision is commonly caused by local inflammatory stimuli, and patients can take amoxicillin, roxithromycin and other drugs under the guidance of the doctor for treatment. 2. Drinking too little water: Drinking too little water can lead to bacterial retrograde, resulting in urethral infection, patients can drink more water, while avoiding spicy and irritating food. 3. Poor blood return: During the surgery, the local lymphatic vessels and blood vessels will be removed, and the poor return can also lead to local swelling. It is recommended that patients should rest more after the operation, improve their mood and lifestyle to promote blood circulation, and go to the hospital regularly for consultation.