Final answer:
The system that alerts healthcare providers about a patient's medication allergies within EHRs is known as a Clinical Decision Support System (CDSS).
Step-by-step explanation:
The kind of system that gives warnings when a patient is allergic to a prescribed medication is a Clinical Decision Support System (CDSS). This system integrates medical knowledge with patient data to provide alerts, reminders, and clinical guidelines to healthcare providers during the decision-making process. CDSS improves patient care by reducing medical errors and ensuring adherence to evidence-based guidelines. Especially in the context of electronic health records (EHRs), CDSS is a vital component of a healthcare IT infrastructure that aids in the detection of drug interactions, allergies, and other critical patient-specific information.