Dr. Jekyll's Serums

"It won't kill you. No, what it will do is far worse. Your body will be your tomb, and you'll be in there with nothing but dreams formed of your own regrets."

- The Evil Queen to Snow White

Jekyll's Serum is a drug featured on ABC's Once Upon a Time. It first appears in the twenty-second episode of the fifth season.

Jekyll's Serum is based on the drug from Strange Case of Dr Jekyll and Mr Hyde.

Serum Effects

 * The original version of the serum was used to turn someone into their evil self. The latter can take the appearance of the person it is applied to, or it can take an entirely different appearance, depending on how they see their inner darkness.
 * An improved version of the serum was developed by adding a flower extract to the original substance, and it separated the personification of inner darkness from their body instead of transforming them.