How long it takes to take a shower after radiotherapy mainly depends on the recovery of the skin, and usually you can take a shower after 3-5 days. Radiation therapy mainly uses radiation to irradiate local tumor foci in order to kill cancer cells, thus effectively shrinking the tumor foci and achieving the purpose of tumor treatment. At the same time of radiation therapy, it will cause certain damage to the normal skin tissues around the irradiation, resulting in mild erythema, redness and swelling of the skin, etc. Bathing is generally not recommended immediately after just radiation therapy. About 3-5 days after radiation therapy, the symptoms of redness and swelling of the skin will gradually be relieved, at this time you can take a bath, but some patients with more serious skin lesions after radiation therapy need to wait for complete recovery before taking a bath. After radiation therapy, it is necessary to pay attention not to use irritating toiletries on the local area, not to rub hard when bathing, and to consult the doctor promptly if there is any discomfort.