The film makes mention of the Candiru, a tiny catfish (also known as the Vampirefish) which has been attributed with the peculiar behavior of swimming into the human body through the urethra (in men) or the vagina (in women), where it lodges itself with its spines. This is not as common an occurrence as the film implies. Only one such incident is known to have happened to a man where a small catfish traveled into the urethra whilst he was urinating in a river. This account has been corroborated by Jeremy Wade in the River Monsters - Amazon Flesh Eaters.
Strong language was dubbed with (for example, using 'freaking') in order to get a PG-13 rating. Not only do the ADR'd lines have a slightly different sound to the rest of the dialogue, but the actors' lips do not match the new dialogue when they speak.