I have pretty bad allergies and this pillow protector really helps a lot for keeping my pillow clean and allergen-free so that I breathe better at night. It protects against most things, like dust & dander but also is antimicrobial to protect against bacteria. Honestly, I don't know how much bacteria grows on a pillow cover, but it's good to have anyway. I do know that having a pillow cover has made a HUGE difference in how well I sleep. A lot of pillows either can't be washed at all or get ruined when washed, so to have a cover that keeps it clean and reducing (or eliminates) how much you have to wash your pillow is great. The cover is machine washable and dryer safe, so I just throw it in with my regular bedding to wash it, which makes it super easy to care for. I'm really happy it.