While the ending of Rosemary’s Baby reveals the heroine has been drugged with Tannis Root, viewers might be surprised to learn the truth about this herb. Rosemary’s Baby is a classic feminist horror movie wherein the newlywed Rosemary moves into an exclusive apartment building and becomes pregnant, only to find herself surrounded by creepy occurrences and ghoulish coincidences. As bodies begin to pile up and Rosemary grows increasingly paranoid, the isolated homemaker becomes convinced that she is at the center of some strange conspiracy. Infamously, the truth turns out to be something even darker than that.

At the ending of Rosemary’s Baby, Rosemary finds out that everyone in her apartment building, her husband, and even her kindly gynecologist are all in on an elaborate plan. They drugged Rosemary months earlier and had forced her to carry the devil’s baby. The cult of Satanists who forced Rosemary to carry the baby to term finally unmask themselves at the end of the story. In Ira Levin’s original novel, they are shocked to discover that Rosemary actually likes her baby despite his parentage. Their plan was a success, and it was only possible thanks to Tannis Root.

Rosemary's Baby's Tannis Root Isn't A Real Substance

The Deadly Plant Was Created By Author Ira Levin

In the book and the movie versions of Rosemary’s Baby, Rosemary is tricked into consuming Tannis Root and wearing a charm that contains the foul-smelling substance. In both takes on the story, Rosemary drinks Tannis Root in health beverages made by her seemingly sweet neighbor. While American Horror Story: Delicate’s Rosemary’s Baby update sees doctors using much more high-tech methods to control their patients, the cultists of Levin’s story rely on this fictional herb.

Tannis Root allows them to control Rosemary, but it's not a real substance. It's more of a plot device to get Rosemary where she needs to be. Rosemary’s Baby has to do some tricky storytelling sleight of hand during Act Two. It needs to be obvious to the viewer that something is wrong with Rosemary’s seemingly healthy pregnancy or else the movie will have no stakes and no tension.

However, it can’t be too obvious that something shady is afoot or viewers will wonder why Rosemary doesn’t just leave her husband and her creepy apartment building behind. Like Levin’s later sci-fi satire classic The Stepford Wives, Rosemary’s Baby reminds viewers that Rosemary isn’t financially independent of her husband. The movie also uses Tannis Root to explain her lack of curiosity.

Tannis Root's Effects On Rosemary In The Movie Explained

The Herb Causes Pain And Confusion

Tannis Root keeps Rosemary extra complacent in the movie adaptation of Rosemary’s Baby. The herb ensures that, even though she does know something is wrong, she never quite manages to get her wits about her for long enough to foil the plan.

Effectively, Tannis Root serves as a mind-control drug or behavior-altering substance. The coven of Satanists believes the herb will allow them to control Rosemary, and while she eventually catches on to their plan, it works for most of the film. Thus, viewers of Rosemary’s Baby will be glad to know that the substance isn’t real.

Tannis Root May Not Be Real But It Appears In An Amazon Prime Show

The Fiction Herb Creates A Bizarre Link Between Rosemary's Baby And The Marvelous Mrs. Maisel

While Tannis Root in Rosemary's Baby isn't a real herb, it has become somewhat synonymous with the iconic 1968 psychological horror. However, it also means that Roman Polanski's timeless satantic cult movie also now shares an unlikely connection with a modern Amazon Prime comedy series - The Marvelous Mrs. Maisel. Tannis Root may not be real, but that didn't stop The Marvelous Mrs. Maisel including it, despite the show having literally nothing to do with the supernatural or satanism.

The link between Rosemary's Baby and The Marvelous Mrs. Maisel emerges due to Marin Hinkle's character Rose Weissman, the mother of the show's central character, Midge Maisel. Among Rose's many erratic quirks is a borderline-addiction to consulting with psychics and mediums. It's this character trait that led to Tannis Root, the fictional herb from Rosemary's Baby, showing up in as unlikely a place as an Amazon Prime show that has literally nothing to do with horror movies.

One of Rose Weissman's various psychics and mediums gives her an intriguing idea to ensure that Midge's life stays on track - place a charm under her pillow. This is exactly what she does in The Marvelous Mrs. Maisel season 1 episode "Ya Shivu v Bolshom Dome Na Kholme". Midge is, understandably, irritated by the discovery, which prompts Rose to try and explain her reasoning.

Rose tells Midge that the charm is filled with Tannis Root, and will ensure that she's kept safe from her life spiraling out of control. While it's entirely possible this is a nod to Rosemary's Baby, it's equally possible that one of the writers of the show chose Tannis Root without knowing it's not a real herb. This seems all the more plausible given that none of the nefarious uses of Tannis Root in Rosemary's Baby hint that it could be used for good luck. Still, thanks to its inclusion, it means that Rosemary's Baby and The Marvelous Mrs. Maisel contains one of the most intriguing and unlikely links between two movies or TV shows that's ever existed.