Choking and suffocation is the third leading cause of home and community death in the United States. Foods are responsible for most choking incidents. But for children, objects such as small toys, coins, nuts or marbles can get caught in their throats. Choking can cause a simple coughing fit or something more serious like a complete block in the airway, which can lead to death.
Although choking can occur in people of all ages, children under the age of three are particularly vulnerable. Older adults also have an increased risk of choking on food.
via: http://www.nsc.org/safety_home/HomeandRecreationalSafety/Pages/Choking.aspx