black stool from pentox

[drew67]

I've recently discovered that my stool is black from taking pentox.  Not a good thing because I'm losing blood. However does this also mean that pentox is very effective and that I would need to take less?

[Jonbinspain]

I'm no doctor, but I can't imagine that there's anything good about rectal bleeding. I would cease taking Pentox and see your doctor ASAP.  

[james1947]

I will second Jonbinspain.
You should stop Pentox and see a doctor as soon as you can.

James