Digestive bitters will increase stomach acid, bile, and pancreatic enzymes, as well as stimulates flushing of the liver. Recommended amount is 1/2 dropper full on the tongue 1-2 times daily right before meals. They do have to contact the tongue to work. Capsules will not work. Drink a lot of water throughout the day when using bitters. They are sold in health food stores. And most contain laxatives.
Fecal odor can also be controlled with prebiotics like fructooligosaccharides (FOS) and yucca root.