Italian to English Medical Medical (general) intestinal symptoms

I'm proofreading someone else's translation of an article about bacteriotherapy in hospital patients treated with antibiotics.

In the description of the different types of symptoms found in these patients, there is "alvo alterno." The translator has translated this as "altered bowel habit" -- which did not look right to me. When I research this online, I find this Italian description: "Tale gruppo presenta feci non formate, molli, in più del 25% delle evacuazioni e dure, caprine, in più del 25% delle evacuazioni. Ad episodi di diarrea intensa si alternano episodi di stipsi più o meno grave."

So it has to do with *alternating* quality or types of bowel movement, but I can't think of how to say this in English. Is there a specific term?

Grazie mille.