A 65-year-old man received docetaxel for prostate cancer. Eight months later, we observed abdominal free air and pneumatosis cystoides intestinalis by computed tomography. Pneumatosis cystoides intestinalis can be caused by various etiologies. However, in the present case, multiple factors could have contributed and we could not specify the exact cause. We reduced the dose of steroid hormone, stopped docetaxel, and followed the patient conservatively with oral antibiotics. The pneumatosis cystoides intestinalis and free air resolved promptly
