Abstract: The author presents a review of evidence on the prophylactic use of paracetamol prior to infant and child immunisation. The research was prompted when the Otago District Health Board was planning its Meningococcal B strategy. The evidence suggests that it was appropriate when the whole cell pertussis vaccine was used, but it was not recommended since the introduction of better vaccines such as acellular pertussis with fewer antigens and fewer side effects. Paracetamol may still be given orally to treat pain and fever that occasionally follows vaccination. Paracetamol pharmacology is presented, along with alternatives to paracetamol.