The health sector is evolving at a rapid pace with a growing task force of health workers ready to defend us from various diseases. Emergency Medical Services(EMS) have therefore become extremely important to empower the health workers. In order to facilitate them to deliver the fast treatment to patients the fast transit of patients to the hospital and access to the right equipment is extremely crucial to save lives. UAV (Unmanned Aerial Vehicle) or drone is a promising candidate for the current problem. However, these drones are prone to be attacked by intruders with a few lines of code. This literature review will shed light on the security threat in the EMS to analyze the risk to UAVs.