My mom has dementia, she has started slapping me in the face or threatening to throw things. Any advice?

In the city I live if someone with dementia or a mental health issue does that you can call the police and they take them to the hospital for evaluation for one week, this is were they (doctors) can exam and run test to see what is going on. Examples, should the person be on medication, is the cause of behavior medication or environment, or is there another underlying cause.
Don't have all the facts, but you may be putting yourself and others endanger. You need to call her Dr because this can become deadly in a very short time. And why are you allowing this behavior?

Good Luck

You need to tell her doctor. There are meds for violent behaviour which this is,

Hello Cdglass - sounds like you got cut off in your prime? Do please have another go at completing your post.