Maybe this can help too.
http://www.drspock.com/article/0,1510,3934,00.html
Not long ago, one of my grandsons -- who I watch CLOSER than I watched my own son -- started complaining about his throat hurting; he was really crying; I went downdstairs to get some ice for his throat because I couldn't see anything wrong with his mouth or throat.
Barely gone sixty seconds, the older two started screaming Come quick........I came back upstairs and there stood the four of them (all under five) AND MY HUSBAND, staring a shinny new penny this kid has thrown up.
Stuff happens.