I, like many people, had trouble choosing a favorite organic molecule. I decided to go with a molecule that has a great impact on my day to day life: sentraline. Sentraline is what is known as an ssri, a selective serotonin reuptake inhibitor. It works by affecting activity in the brain (specifically serotonin levels) in order to treat illnesses like depression and obsessive compulsive disorder. Like any drug, it does not work for everyone, and can have side effects ranging from psychological (e.g. suicidal thoughts) to physical (like nausea). However, speaking from personal experience, if one does not experience severe (or any) side effects it can make a huge difference concerning the treated disorder. Though development of the drug was begun as early as 1971 by various chemists working for the Pfizer company , it was not FDA approved until 1991. More than 40 years later, the drug is still going strong, with a generic version becoming available in 2006.