92 yr. mom back&forth w/ constipation then soft stools..meds&food changes don't help?

Med and food changes: ALWAYS work when done systematically. In my experience patients / docs change things too frequently and CAUSE alternating const./diarrhea. Should be on a baseline of bulking fiber - psyllium - at moderate dose AND a stimulant such as senna then add osmotic agent such as PEG and increase dose as needed to have one smooth BM/day. If not effective see doc to r/o anatomic problem.