Aceclofenac is a widely prescribed nonsteroidal anti-inflammatory drug (NSAID) used in the management of pain and inflammatory disorders. Although generally considered safe and well tolerated, rare but severe hypersensitivity reactions such as anaphylactic shock may occur and can be life-threatening without prompt treatment. We report the case of a 39-year-old female who developed acute abdominal pain, irritability and hypotension shortly after ingesting oral aceclofenac for pain relief. On presentation, her blood pressure was 90/60 mmHg with maintained oxygen saturation. Laboratory investigations showed mild leukocytosis and elevated inflammatory markers, and she had no prior history of drug allergy. The close temporal association between drug intake and symptom onset suggested aceclofenac-induced anaphylaxis. Immediate discontinuation of the drug was undertaken, and the patient was treated with intramuscular adrenaline as first-line therapy, followed by intravenous corticosteroids, antihistamines and supportive care, resulting in rapid hemodynamic stabilization and complete recovery. Causality assessment using WHO–UMC criteria categorized the reaction as Probable/Likely, and the Naranjo Adverse Drug Reaction Probability Scale also indicated a Probable association. This case emphasizes the importance of early recognition, prompt adrenaline administration, structured causality assessment and pharmacovigilance reporting to prevent recurrence and improve patient safety.