This object contains Ellen's despair and is the ultimate key to killing her body.
Ellen describes it as a "small candy-colored glass bottle with a cute design, like one for perfume." The bottle gives off an aroma of sweet confectioneries, similar to that of Ellen's mother. Due to the latter, Ellen deduces that her mother was the key to killing her.
The Cute Little Bottle is introduced in the third chapter, where Ellen ponders on the Black Cat saying that witches were immortal. While any body wounds she received almost instantly healed up, wounds of the heart seemed to make her illness resurface on her illusionary body and give her the feeling that she might someday disappear. Hearing out her inquiry, the cat tells her that she can in fact die if it is her desire to do so and gives her a little bottle. He explains that the key to a witch's death is despair and that the bottle contains Ellen's main source of despair. Curious about the aroma resembling that of her mother's, Ellen loosens the bottle's lid. The moment when the sweet scent reached her nose, she is greeted by the Grim Reaper's blade facing her neck and preparing to decapitate her. Convinced that this was certainly a premonition of death, Ellen quickly tightens the bottle's lid and throws it against the floor out of fear. Later in the chapter, she stores the bottle in the Medicine Room.
In "Begin", when Ellen's (in Viola's body) path was blocked by the huge patch of roses, she recalls the Cute Little Bottle she stored away and returns to the Witch's House, believing it to be the key to making the roses wilt and destroying the witch's body.
The Witch's House
The item is located in the 5th Floor's Medicine Room, where Ellen's silhouette can briefly be seen standing in front of a shelf with a bloody message scribbled on its glass cover. Interacting with the shelf once will give Viola the Cute Little Bottle. Interacting with the shelf a second time will display the following message: "MEDICINE TO KILL ME."
"Medicine that kills the witch's roses. Smells sweet." —Description of the Cute Little Bottle.
The Cute Little Bottle is a key item that allows Viola to leave the Witch's Forest. After successfully escaping from the Witch's House, the player must return to the Rose Patch and pour the contents of bottle on the roses that initially blocked their path. Upon doing so, the roses will vanish, allowing you to continue down along the Forest Path where you will get your respective ending.
In Version 1.07's "___" Ending, Viola never retrieves the bottle and the roses simply vanish after an hour-long wait. This reveals, along with information from the novella, that if Ellen had simply waited, Viola would have succumbed to her wounds and the "witch's" magic would have eventually faded away.