Hi, this is a curious question. I was told (by a doctor) that virus/bacteria/fungus/etc.. keep a balance in one's body, and that if they weren't in balance you'd likely get an infection by the one with the most influence.

For example, lets say I killed all the bacteria in my body. All other bad affects of that aside, I would likely get a viral or fungal infection according to this doctor.

I'm wondering if this is true, haven't seen anything about it online. Thanks.