Black Stool After Wine

Hi Everyone :)

Like the subject says, I experienced a nice black stool this morning. I had two glasses of red wine last night. I've googled and red wine does change stool colour but to green, not black. I had a stool occult test a month ago and it was negative. Any insight?

Did you eat any dark veggies, like spinach? Food can make your stool look dark too.

I'm wondering if the alcohol aggravated something? As far as I know I don't have an ulcer. If an ulcer is seen on ultrasound then I definitely don't have one.