My flatmate happens to be cultivating several members of the buttercup family, and aconite is among them. Had she known this would adversely affect a tenant's health, I'm sure she would have found a way to keep them elsewhere...given the toxicity of the plant, especially when ingested, perhaps it would be a worthy endeavor to find a substitute. I will discuss this with her immediately and aid her in discovering a less potent alternative.
Edit: She voiced very strong reservations about getting rid of the plant, and I haven't yet been able to communicate the urgency of the situation. While she is protective of her work, I have never known her to be unreasonable. We'll have to work toward some compromise. If you have any suggestions, feel free to post them here, as I doubt she is in the spirit for company.
My sincerest apologies,