Thyroiditis can often lead to initial thyrotoxicosis and it is important to differentiate among the causes as many cases do not require antithyroid drugs. We present a case report of a 48 year old lady who presented with 10 days history of fever, fatigue, myalgia and a painful goitre after returning from a cruise at Caribbean. Examinations showed pyrexia of 38 C but no localising signs of infection. She had a smooth tender goitre and no signs of thyrotoxicosis. Investigations revealed modestly raised white cell count and C-reactive protein and deranged liver function tests with significant ALT rise. Thyroid function tests showed TSH of 0.07 mIU/l (0.255.00), fT4 of 29.2 pmol/l (9.023.0) and fT3 of 7.3 pmol/l (3.56.5). Interestingly, thyroid function tests were completely normal seven days ago. Thyroid auto-antibodies were negative and thyroid uptake scan showed no thyroid tracer activity. Two months later, her symptoms had disappeared. There was no palpable goitre and thyroid function tests showed normal fT4, normal fT3 and a slightly high TSH suggesting subclinical hypothyroidism. Inflammatory markers and liver function test had normalised. She was diagnosed to have de Quervains thyroiditis and was monitored without antithyroid drugs. De Quervain thyroiditis is thought to be due to a viral illness and the management is conservative. Treatment with antithyroid drugs is not indicated as the initial thyrotoxicosis is linked to cytotoxic T-cell mediated release of thyroid hormones into blood stream rather than increased thyroid hormone production. A close watch should be kept on thyroid function tests as patients go through a hypothyroid phase due to depletion of thyroid hormones before returning to euthyroid phase in most cases.