I don't know the title of the movie but I do know what it's kind of about...
There's this forest which gets ruined by a gas leak or something and this girl gets poisend so these other kids or something go on an adventure to find a plant that can save her life and its set in the 90's I don't know specifically, do you know what movie it is?:)

MovieLover88,
Try this movie,

Plot Summary for
Once Upon a Forest (1993)
This animated wildlife film provides an environmental friendly message that humans are a malicious, careless breed. Three chrubic little animals hacve to rescue their friend who has been overcome by poisonous gas.

Summary written by John Sacksteder {[email protected]}

http://www.imdb.com/title/tt0107745/plotsummary
-- Ace