Aaron Hartman, MDFunctional Medicine Specialist | Clinical Researcher

The average person swallows over one trillion bacteria every single day #GutHealth #ImmuneSystem

22 Dec 2025 · 1 min

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0:44

Short excerpt from a YouTube video by Aaron Hartman, MD arguing that the average person swallows about one trillion bacteria per day and that oral bacteria exposure likely dwarfs doses from commercial probiotics (speaker contrasts ~1 trillion swallowed vs. ~100 billion CFU in a probiotic). The clip frames the mouth as a major determinant of gut health and microbial seeding.

Questions this video answers

About one trillion bacteria per day (speaker estimate).

Approximately one hundred billion CFU (speaker estimate for a 'fancy probiotic').

Chapters

You said this thing that just boggled my mind. That made me think a little bit. And you said, the average person swallows. And I may get this number wrong, but I think it was like a trillion bacteria a day. Trillion bacteria a day, Right. And when you said that, I was like, I use my fancy probiotics that have, like, a hundred billion, you know, CFU's and. And, like, but they don't compare 10 times more. You literally, in your mouth, you make 10 times more bacteria, you swallow every day. Then you take a fancy probiotic. So really, your mouth becomes set your gun up for health or not. All of a sudden, it's like your mouth is way more important than any probiotic you might take, and it can set your gut up for health or disease.