Is aloe vera juice good for diverticulitis?

No: It won't hurt but will not help. Diverticulitis is an infection around a diverticula and needs to be treated with antibiotics. If they do not resolve the infection, then surgery is required. To reduce the formation of diverticula and possibly prevent diverticulitis, dietary fiber is needed. The simplest way to get enough fiber is to take metamucil or an equivalent daily.