Alison Lohman had a small role as a cancer patient but was cut out of the movie. Since she shaved her hair off for the part, she had to wear a wig throughout her next movie, White Oleander (2002).
The character Joe Darrow was written with the intention of Harrison Ford taking the part. Ford turned down the role to take a year off from movies.
The movie is dedicated to Katharine Curtiss (wife of assistant producer/first assistant director Alan Curtiss), who died during production. Curtiss is also the name on the realtor sign in front of Joe's home.
The scenes at the waterfall weren't filmed in Venezuela. Logistics and budget necessitated shooting these scenes on Kauai, Hawai'i, where, interestingly, they needed to create the waterfalls entirely by CGI.
The realtor sign in front of Joe's house has an actual phone number of 312-257-2738 for Curtiss Real Estate on it instead of the usual 555 exchange. The 257 exchange is invalid for the Chicago 312 area code.