Some substances heal, others harm: and sometimes, the same molecule can do both. This chemistry-rich (but non-technical) course explores the surprisingly thin line between pharmaceuticals and poisons. We will learn how animal venoms inspire lifesaving treatments, how aspirin traces its roots to the dye industry, and why the term 'toxin' is so often misused. We will also examine the dramatic history of FDA regulation, marked by scandal, tragedy, and reform, and how it continues to shape what ends up in our medicine cabinets. From scorpion stings to Gila monster hormones, this course offers a fascinating and sometimes unsettling look at the chemistry behind what we choose to swallow.