"A gut instinct…", "misery guts", "guts for garters", "gut wrenching"; we've been obsessed with it for centuries, but increasing evidence proves a healthy gut plays a crucial role in a healthy body & mind. Aoibhinn discovers the challenges of getting probiotics into our gut when most bacteria die in the acidic juices of our stomach, Kathriona finds out why many researchers now consider the gut to be our second brain and are investigating which bacteria could be key to developing a range of psychobiotics (mood controlling bacteria) and Jonathan reveals how analyzing the evolving gut microbiota of infants could provide new opportunities for improving infant health and the optimising infant milk formula composition.