Fermented cabbage wipes the floor with probiotics. Korean kimchi or German sauerkraut, eaten raw and unheated, will pump your gut so full of lactobacillae it's like re-formatting it. And it's cheap. And works. Just don't buy it packaged, 'cause then it's as dead as a rock (otherwise the packaging would pop, which should be obvious).

I'm like the Bear Grylls of bowel movement optimization. 😂