Rectum, colon polyps:

Bloody red, painless, blood and stool do not mix Together.

Ulcerative colitis:

Bleeding mixed with mucus or was pus and blood, accompanied by abdominal Pain, fever, frequency and so on.

Rectal cancer:

Red or dark red bloody, was drop attached to the stool surface; Late often appear pus and blood will be accompanied by Anorectal fall, weight loss, stool habits change and other symptom.