I think it's about the movie Innerspace (1987):
American pilot Lieutenant Tuck Pendleton (actor Dennis Quaid) takes part in an experiment in which he will greatly decrease in size and in an aircraft similar to a submarine will examine the interior of a rabbit. But the techno-terrorists ruin all plans and steal the syringe, which contained a miniature Tak.
By mistake, the contents of the syringe fall into the hypochondriac Jack Putter (actor Martin Short). Now the terrorists begin to hunt for the unsuspecting Jack. The only one who can help him is Tuck's girlfriend, Lydia (Meg Ryan), a journalist.