Jul 20, - Rectal bleeding, also known as haematochezia, refers to the Associated symptoms include discomfort and pruritus ani (itchy bottom). Anal. Feb 28, - Hemorrhoids. These are probably the most common cause of visible blood in the lower digestive tract, especially blood that appears bright red. Hemorrhoids are enlarged veins in the anal area that can rupture and produce blood, which can show up in the toilet or on toilet paper. Anal fissures.