If the bleeding CONTINUES and is a LOT, I repeat, a LOT of blood loss...sometimes...very rare!!!...a diverticulum (also very common - a weakness in the wall, sorta like a hernia) can rupture. This is an ER visit...and immediate surgery.

Are your SURE it was blood? If only a little "red", did you eat beats?

That said...still...to be sure...check in with your doc.

In the meantime...don't panic.

Black stools/BMs indicate bleeding higher up in the GI tract OR something you consumed(Pepto Bismol).

P.S. Here's some additional info.:
http://www.healingdaily.com/colon-kidney-detoxification/hemorrhoids.htm

If Bb is in the bowel...ask your doctor if it is okay with him/her to take 2 Pepto Bismol tablets and 1 Zantac before bed every night for ONE WEEK ONLY.

This is why:

Int Microbiol. 2001 Dec;4(4):209-15. Related Articles, Links

Susceptibility of motile and cystic forms of Borrelia burgdorferi to ranitidine bismuth citrate.

Brorson O, Brorson SH.

Department of Microbiology, Vestfold Sentralsykehus, Tonsberg, Norway.

Gastrointestinal symptoms accompanying Lyme disease have not been considered in the treatment of Lyme patients yet. Here we examine the effect of ranitidine bismuth citrate (RBC) on motile and cystic forms of Borrelia burgdorferi in vitro, to determine whether it could cure this bacterial infection in the gastrointestinal tract. When motile forms of B. burgdorferi were exposed to RBC for 1 week at 37 degrees C, the minimal bactericidal concentration (MBC) was > 64 mg/ml. At 30 degrees C, the MBC was > 256 mg/ml. When the incubation lasted for 2 weeks at 37 degrees C, the MBC dropped to > 2 mg/ml. Bismuth aggregates were present on the surface of B. burgdorferi when RBC > or = MBC, as shown by transmission electron microscopy (TEM). Cystic forms of B. burgdorferi, exposed to RBC for 2 weeks at 37 degrees C, were examined by cultivation in BSK-H medium (Sigma B3528). They were stained with acridine orange (pH 6.4, pH 7.4) and studied by TEM. The MBC for RBC for young cystic forms (1 day old) and old cysts (8 months old) was estimated to be > 0.125 mg/ml and > 2 mg/ml, respectively. Bismuth aggregates were attached to the cysts and, in some, the pin-shaped aggregates penetrated the cyst wall. The bismuth aggregates also bound strongly to blebs and granules of B. burgdorferi when RBC > or = MBC. When B. burgdorferi is responsible for gastrointestinal symptoms, bismuth compounds may be candidates for eradication of the bacterium from the gastrointestinal tract.

PMID: 12051564 [PubMed - indexed for MEDLINE]

http://64.233.167.104/search?q=cache:rsmlwBhlJtoJ:www.chsd.org/1704.cfm+blood+in+stools&hl=en

Also, I don't have a RX for Zantac now -- what dosage is it? I will try to call my doctor (out on fridays) and get a RX -- and try this -- does this mean stopping everything else (abx and all supplements enzymes for stomach) while trying this ?
I am desperate to stop my "malabsorption" -- four + months of going to bathroom 10-20x a day and it is getting worse since started back on Flagyl and Zithromax.

I would still go see a gastroenterologist (sp?).