Don't give your child toys that have small parts that can be swallowed or become lodged in a child's windpipe, ears or nose, such as doll accessories, small snap-together blocks or beads or puzzles with small pieces. While there is a "truncated cylinder test tube" with a regulation size of 1-3/8 inches in diameter, children have choked on objects larger than this. This clear plastic tube allows things to fall through it that are too small to give to children under 3 years of age (but items marked for children 3 and over do not have to pass this test). As a general indicator, you can use a home-made version - an empty toilet paper tube. If an object can fit inside the this tube, it could be a choking hazard for a baby or child.
The worst offenders are pieces of broken balloons that children ingest, and the marbles and small balls that often come in vending machines or games intended for older children.