Nausea and vomiting are common presentations in family medicine and are often attributed to acute infection, migraine, or self-limiting gastrointestinal illness. When symptoms persist or recur, especially in the presence of competing diagnoses, underlying systemic causes such as hyperthyroidism may be overlooked.We present a descriptive case report of a 39-year-old woman whose diagnosis emerged through serial reassessment during an acute admission and integration of longitudinal clinical history across multiple healthcare encounters.This case illustrates a gastrointestinal-predominant presentation of Graves disease complicated by concurrent bacterial tonsillitis and a history of migraine, highlighting the diagnostic challenge of symptom overlap in primary care.Persistent symptoms despite appropriate treatment should prompt clinicians to revisit the differential diagnosis. Recurrent tachycardia and menstrual irregularities may be important clues to an underlying endocrine disorder. A longitudinal, whole-person approach may reduce diagnostic delay and repeated healthcare utilisation.A 39-year-old woman with well-controlled asthma and episodic migraines presented with fever, cough, sore throat, and one week of recurrent vomiting, escalating to approximately 20 episodes on the day of admission and associated with epigastric pain. Examination revealed tachycardia (heart rate 110 bpm), bilateral tonsillar exudates, epigastric tenderness, and possible neck fullness that was difficult to assess due to body habitus. Initial investigations showed leukocytosis with neutrophilia and mild hypokalaemia, with otherwise unremarkable renal and liver function tests. She was treated for bilateral bacterial tonsillitis with oral amoxicillin-clavulanate and symptomatic therapy for presumed post-tussive and migraine-related vomiting. While respiratory symptoms and headaches improved, vomiting persisted. Further history revealed recurrent gastrointestinal disturbances, intermittent unexplained tachycardia documented during prior clinic and emergency visits, and irregular menstrual cycles over the preceding year. Thyroid function testing demonstrated suppressed TSH, markedly elevated free T4, and positive thyroid antibodies, confirming Graves disease. Carbimazole was initiated with subsequent clinical and biochemical improvement.Hyperthyroidism should be considered in patients with persistent or recurrent nausea and vomiting, particularly when accompanied by systemic features such as tachycardia or menstrual irregularities. This case highlights the value of continuity of care and reflective reassessment in family medicine to prevent diagnostic delay.