Marbled bowel movements. what is the problem?

I do not know: What we eat and drink certainly has a direct relationship on the size and consistency of our bm's. Certain bowel illnesses may cause smaller shaped bm's or elongated bm's, etc. If the problem persists, and this is a definitive change in your normal bowel habits, etc. Then i would get a GI eval to be safe. Best wishes.

Not Enuf water: You need to drink more water! eat more fruit and fiber. Try 6-8 glasses of water daily and 5 fruits and vegetables daily.

Scybalous stool: Hard pellet-like (scybalous) stool, associated with passage of mucus, suggests several possibilities: constipation-variant irritable bowel syndrome (c-ibs), rectal dyssynergia due to altered rectal tone/sensation, partial obstruction likely due to adhesions. Work-up may include: colonoscopy to evaluate the bowel, sitz marker testing to distinguish normal- versus slow-transit constipation, ct scan.