What is the Difference between reflexes and reactions?

Reaction is a feeling or action in response to something that has happened. Reactions can be spontaneous, but most are under conscious control.

A reflex is a physical non-conscious action. A doctor uses a rubber hammer and taps a certain spot on the knee, ankle, elbow, or wrist and the body part further away (distal to the hammer strike) responds in reflexive movement (a jerking motion forward or up).