Kate investigates eucalyptus. It's found in throat lozenges and chewing gum, but what exactly is it, where does it come from, and why is it so good at clearing the airways? In Australia, Kate meets one of the world's cutest animals: the koala, raised from birth on a diet of eucalyptus. Kate finds out that eucalyptus is highly toxic, but a local farmer shows her the clever way it's made safe for human consumption. Jimmy's puzzling over pickles. Most pickled goods contain vinegar, but pickled cabbage - or sauerkraut - has no vinegar at all, despite tasting decidedly vinegary. So what's going on? To find out, Jimmy visits a very chilly Poland, the home of sauerkraut, before learning about a remarkable new use for sauerkraut juice in a French power station.