uzbuđivati

1. to excite; to thrill
   Ta ideja me stvarno uzbuđuje. — That idea really excites me.
   Putovanja ga uvek uzbuđuju. — Travelling always excites him.
2. (uzbuđivati se) to get worked up; to get upset
   Ne uzbuđuj se zbog sitnica. — Don't get worked up over little things.
   Lekar mu je rekao da se ne uzbuđuje. — The doctor told him not to get upset.
3. (sexually) to arouse; to turn on
   Uzbuđuje ga njen glas. — Her voice turns him on.

The perfective is uzbuditi; "Ne uzbuđuj se!" is a common way to say "Calm down!".