Hematochezia

Japanese 血便 (ketsuben), literally bloody stool, also 下血 (kegetsu), literally bloody descent, led me to the English hematochezia, which I didn't know. It's funny that kanji is much more transparent than European words, which are many times derived from Greek. Hematochezia is composed of hemato (blood) + chezia (from chezein, to defecate), thus meaning passage of bloody stools.