This is a case study adapted from "Teaching Chemistry Through the Jigsaw Strategy" by the Quality Education Fund, Hong Kong (2007). It brings to attention the importance of chirality and the structures of molecules in a biological context. It describes the real events surrounding the drug Thalidomide before it was pulled off of the market. This drug has recently been introduced back to the market but under stricter regulations. One enantiomer of the drug was used to treat epilepsy and as a sleeping aid but the other enantiomer of the drug resulted in terrible developmental defects in children when taken by pregnant women. The slides used for the introduction and discussion of the case study are included in the file.