This answer does not belong to me. Its URL is copied and hopefully this will help if you are talking about the Death Daisy Potion:
http://wiki.answers.com/Q/Where_do_you_find_death_daisy's_in_sims_2_castaway_ps2
Hope this helps!
It tells you what you need and other stuff that's useful.
I'm now in love with the little "despicable" Minions from Despicable Me. I saw the second film a few weeks ago and loved it and now I adore the Minions as well. They're too cute! Who doesn't love Minions? And I might not have a new sig and avy up for a while since I'm saving Images to my 3DS Camera. Look on Examiner.com to read what they're saying in the first film's credits.