Well-meaning, terminally upper middle-class, and politely resigned to life's horrors, she waggles her finger at the animal as if it were a misbehaving servant and attempts to banish it with the authoritative cry: "Out, do you hear me?"
Her problems with evicting the toad are compounded by her mother's delusion that the creature is a former lover - so where others can only hear croaks, Minnie's senile dementia allows her to hear love elegies.
And as if this weren't enough for Sylvia, her teenage daughter Sarah thinks she might be a lesbian. Pat Rowe's first play for theatre, Toad, dabbles in the murky waters of how mothers' mistakes can become daughters' tragedies, and comes up with some pleasingly untidy solutions.
Minnie's dementia exposes the complex web of emotions precariously holding her and her daughter together, and how Sylvia's do-gooding concern masks a desire to control and, so, take revenge on the mother who sent her away to boarding-school when she was eight.
Jacqui Somerville's gentle and funny production balances on Alwyne Taylor's portrayal of Sylvia, who reeks of metaphorical labradors and green wellies as she puts up a front to conceal the abandoned child within her.
The complexity of her bluff Englishness is highlighted by the inescapable Polishness of her mother - and Ruth Posner, herself a survivor of the Warsaw Ghetto, throws herself into the role of the exotic pensioner whose madness highlights a fantasy-world where she selfishly has no time for any scenario in which she is not the romantic heroine.
There is perhaps no work of literature that digs so insidiously at the concept of the romantic heroine as Les Liaisons Dangereuses, and its enduring fascination is being celebrated once more with a new adaptation of the novel by Patrice Lambert and Alec McCallum.
As the film world focuses on Cruel Intentions, which transforms Laclos's novel into an American 'teen flick, Tenth Planet Productions pays its own tribute to the novel's modernity by giving Valmont dark glasses and adding funky music. Alexander Holt's production embodies a certain degree of the book's malignant flirtatious flutter and turns in good performances from Harry Meacher as Valmont and Elizabeth Jasicki as Madame de Tourvel. It is unfortunate, therefore, that the garish set design and miscalculated music spoil it. Baudelaire famously said: "If this book burns, it burns as only ice can burn," but the production's tastelessness makes the ice seem merely to be dissolving in a glass of Bacardi and coke. If it forgot the innovation, and stuck to the flirtation, it might end up being a significantly better evening.
`Toad' (0171-794 0022) to 11 July: `Les Liaisons Dangereuses' (0181-340 3488) to 4 July