Antibiotics often killed off good bacteria species in our guts. Are there any ways to replenish them, other than the unpleasant fecal transplant procedure? A search on this topic mostly return recommendations on healthy diet and probiotics. I reckon these can only help surviving species, and those species that have been eradicated are gone for good. Or could their kin somehow re-colonize our guts? Some suggest soil-based organisms, but I am unable to find any supporting scientific evidence.