#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;


my $string = 'WhateverFooBlahBarMoreFooStuffBarMore';

my @words = $string =~ / (?<=Foo) (.*?)  (?=Bar) /gx;

print Dumper \@words;

##</code><code>##

Output:
$VAR1 = [
          'Blah',
          'Stuff'
        ];