I use Bachs rescue remedy and it seems to take the edge of her. Without it, she is a nervous wreck with fireworks (we are in edinburgh and have a few firework displays throughout the year). However, although it doesn't completely calm her it is a dramatic improvement and just gets a bit wound up. Also chamomile in their feed a few days before would settle them (Chamomile tea is most useful) and also spray lavender in the rooms.

Hope that helps