Imagine you pick up two identical-looking pills—one saves lives, the other is toxic. Welcome to the world of chirality, where molecular handedness determines everything. This episode explores how some molecules exist in left- and right-handed versions, why life only uses one type, and how a single flip can be the difference between medicine and poison.

We uncover the tragic story of thalidomide, a drug disaster caused by chirality, and investigate why smell, taste, and even DNA depend on molecular symmetry.

Could alien life use the opposite handedness of molecules? And if so, would they be able to eat our food? It’s a world of molecular doppelgängers—where the smallest changes have the biggest consequences.