The culprit behind a cat's red gums and bad breath is often the overgrowth of harmful bacteria in the mouth or gut. When there's an excessive presence of harmful bacteria in a cat's gut microbiome, the foul odor they produce can enter the bloodstream and eventually cause bad breath in the cat.

The gut microbiome residing in a cat's digestive system is closely related to the oral microbiome living in its mouth. Oral health issues such as gum inflammation, cavities, and bad breath can lead to excessive inflammation, impacting not only the cat's mouth but also its overall health. It's important to practice good oral hygiene to manage a cat's oral microbiome. Additionally, certain ingredients in a cat's diet or treats can negatively affect its digestive system, leading to imbalances in the microbiome and causing bad breath. Supplementing deficient nutrients through nutritional analysis can help increase microbial diversity in the gut microbiome.