Research is exploring the connection between the oral microbiota and various diseases, including periodontitis, colorectal cancer, and cardiovascular diseases. The oral-gut axis is being studied for its role in immune modulation and systemic inflammation, with some research focusing on the microbiota's influence on specific conditions such as depression and allergic rhinitis. The relationship between the microbiota and disease appears to be complex, involving multiple axes, including the gut-brain axis, and various mechanisms such as immune suppression and metabolic reprogramming.