Peri-operative anaphylaxis can occur in response to many drugs used during anesthesia like neuromuscular blocking agents (NMBAs), antibiotics, colloids, and hypnotics. NMBAs are the most common cause. Diagnosis involves considering the time of reaction, drug history, tryptase levels and diagnostic tests like skin tests. While challenging to diagnose, it is important to identify causative agents to avoid severe reactions during future procedures. Proper history taking and diagnostic evaluation can help determine risk factors and manage patients experiencing peri-operative anaphylaxis.