If you live in an old house, there’s probably lead in the paint. A pet or child who chews on the paint can become violently ill. Likewise, popcorn ceilings in homes built before 1978 could contain asbestos, which has been linked with breathing, lung and heart ailments, and even cancer.
If you’re removing your popcorn ceiling, wear a respirator. Likewise, if your lead-based paint is chipping or peeling, you should remove it. If you do it yourself, get everybody out of the house first, wear a respirator while you work and try to create a little dust as possible.
Even better for both lead and asbestos: Hire a pro to do the cleanup.