Last updated: Apr 28, 2016

Q: I've been noticing blood in my poop. Should I be concerned?

I don't want to alarm you, but you should have this checked out ASAP. How much blood have you been noticing, and what color? And is it mixed in with the stool or on top? These are details that will help your doctor pinpoint where the bleeding is coming from. If you spot bright red or maroon blood on the surface, you may have an anal fissure (a tiny tear), which can happen from passing large or hard stools. While they can be painful, the cuts are typically nothing to worry about and heal on their own within a few weeks. Anal fissures that don't get better within six weeks may require medicine or surgery—but that's pretty rare.

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Blood on your poop, or bleeding during or between bathroom runs, could also be a sign of hemorrhoids, which are swollen veins in your anus or rectum. You can develop them from a variety of causes, including straining when you go, constipation, or pregnancy, when there's extra pressure on the veins. Often hemorrhoids can be made less troublesome with dietary tweaks, like drinking plenty of water and adding fiber to help soften stools. In the meantime, your doc may suggest using an over-the-counter hydrocortisone cream to help with the swelling and itchiness.

However, red or darker blood in the toilet or mixed in with the poop might indicate something more serious, such as colon cancer or inflammatory bowel disease (IBD). The most common types of IBD are Crohn's disease, which involves inflammation anywhere in your digestive tract, and ulcerative colitis (UC), in which the inflammation specifically affects the lining of the colon and rectum. IBD can also cause abdominal pain, fever, and weight loss when it flares up. Mild IBD symptoms can often be controlled by medication, combined with avoiding certain foods (including fatty and high-fiber kinds, as well as dairy), eating smaller and more frequent meals, drinking plenty of water, and exercising. In extreme cases, surgery or additional medications may be required.

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Those with Crohn's disease and UC are also at higher risk of developing colon cancer, which is why it's important to bring up any blood in your number two with your doctor to figure out the reason behind it and start treating it as quickly as possible.

Health’s medical editor, Roshini Rajapaksa, MD, is assistant professor of medicine at the NYU School of Medicine.