This week Prof. David Pritchard gets to the bottom of why parasites may help to get rid of allergies, Elizabeth Bernays describes how caterpillars acquire a taste for plants containing toxic chemicals when they have parasites, Chris Smith visits Westbourne High School in Ipswich to carry out fitness experiments for Healthcare Science Week, and Dave and Derek go bang with an explosive electrolysis experiment in the Naked Scientists Laboratory. Like this podcast? Please help us by supporting the Naked Scientists)