Rectal bleeding may show up as blood in your stool, on the toilet paper or in the toilet bowl. Blood that results from rectal bleeding can range in color from bright red to dark maroon to a dark, tarry color.

Call Emergency for emergency medical assistance

Seek emergency help if you have rectal bleeding and any signs of shock:

• Rapid, shallow breathing
• Dizziness or lightheadedness after standing up
• Blurred vision
• Fainting
• Confusion
• Nausea
• Cold, clammy, pale skin
• Low urine output

Seek immediate medical attention

Have someone drive you to urgent care or an emergency room if rectal bleeding is:

• Continuous or heavy
• Accompanied by severe abdominal pain or cramping
• Accompanied by anal pain

Schedule a doctor's visit

Make an appointment to see your doctor if you have rectal bleeding that lasts more than a day or two, or earlier if the bleeding worries you.

Generally, people younger than 40 who whose rectal bleeding is from an obvious cause, such as constipation, don't need testing. However, many doctors recommend tests such as colonoscopy for people older than 40 to rule out the possibility of also having cancer that's contributing to the bleeding.

Source: http://www.mayoclinic.org/symptoms/rectal-bleeding/basics/definition/SYM-20050740?p=1