is it true that eating spicy foods kills bad bacteria inside of you?!

No not true.
Your immune system fends off bad bacteria.
You actually need bad bacteria in your body to keep healthy.
It's bad bacteria that builds strong immune systems to fight them back.
Sounds confusing, but it's not.
The latest studies show that we have become to sterile which has hurt our ability to fight off disease.
The culprits?
Antibiotics, Lysol and bleach to name a few, now we have hand sanitizing gels that are making it worse. We over did it and now we don't have enough germs in our bodies( read the latest reports).
Don't try to kill bacteria in your body. That's the job of your immune system!

Eating garlic and onions are a great way to stay healthy. There are garlic pills and such also. The only thing I have ever heard about spicy foods is that it can speed up your metabolism.