Barbara is an aide to Dr. Cecil Pritchfield in "Send in Stewie, Please".
She admits Stewie to the Dr.'s office when he's ready, which mildly annoys him, but he still hopes that she can get Adele concert tickets that she wants, although he admits to the Dr. that it is a lost cause as they've been sold out for weeks. She also brings Stewie some tissues when be breaks down after the doctor observes that he is a lonely boy.