Both cerebellum and medulla oblongata control involuntary actions. What's the difference?
The cerebellum is responsible for precision of voluntary actions and maintaining the posture and balance of the body. It is also involved in some cognitive functions like attention, speech and some emotional functions like regulation of fear and pleasure responses.
Medulla oblongata contains the cardiac, respiratory, vomiting etc. centres and deals with involuntary actions including blood pressure, salivation and vomiting etc.