Is it possible to recover my intestinal flora?

Some years ago (when i was a kid) i had some kind of gut infection never went to see a doctor, i tried to cure myself doing some pretty stupid stuff to "clean my colon", i probably destroyed a huge amount of my intestinal flora in the process. Now i have a lot of food malabsortion problems and intolerance. Almost any food i eat give me diarrhea and make me feel gassy.