Natto, Bacillus subtilis, var. natto, grown on soy beans can be considered as a primitive herb.
It is useful, among other things, for acute & chronically intractable loose stool evacuation.
I have seen children with diarrhea of several days duration eat Natto beans on a salt cracker return to normal evacuation.
Adults with chronic "loose" stool respond well too, usually a bit slowly. These are individuals who have been unsuccessfully medicated, with both over the counter & prescribed treatments; including the gamut of popular "pro-biotic" supplements.
With adults there are variables to acknowledge; sphincter tone, medication side effects, psychological factors & possible pathology. These details are not being discussed here.
Counter-indication for use of Natto is for those taking blood thinner medication, & is also not recommended for those with the type of allergy to anchovies.
You can make Natto yourself quite easily from powdered Japanese spore culture & boiled soy beans. It keeps refrigerated well.