More than 300 million people worldwide suffer from thyroid disease, but 50% of them are unaware of the disease. The thyroid gland is a small organ with important functions. The thyroid gland produces, stores and releases thyroid hormones into the bloodstream to regulate the body’s metabolism. These hormones are important for maintaining the proper functioning of all tissues and organs in the body. There are two forms of abnormal thyroid function: hypothyroidism (the action of the thyroid gland is underground) and hyperthyroidism (the action of the thyroid gland is high), with hypothyroidism being the more common of the two. Symptoms vary in patients with thyroid disease, but are often mistaken for other conditions such as pregnancy, menopause or depression. Patients with hypothyroidism often have the following symptoms: fatigue, sleepiness and/or weakness, fear of cold, memory loss, weight gain or difficulty losing weight (even with controlled diet and exercise), depression, constipation, menstrual disorders and/or infertility, joint and muscle pain, thinning and brittle hair and nails and/or dry, flaky skin. Complications of long-term, untreated hypothyroidism can be serious and include a slow heart rate, even coma, increased systolic blood pressure and increased blood cholesterol levels (both of which are risk factors for atherosclerosis and heart disease), female infertility and an increased risk of Alzheimer’s disease. Patients with hyperthyroidism often exhibit: weight loss despite normal diet, nervousness, anxiety, irritability, anger, rapid heart rhythm (often over 100 beats per minute), protruding eyes, staring, hand tremors, muscle weakness, fatigue, hair loss, increased bowel movements, faster nail growth than before, thin and extra smooth skin, fear of heat, sweating and menstrual disorders. If left untreated, hyperthyroidism can lead to cardiac arrhythmia and even heart attack. In addition, hyperthyroidism increases the risk of osteoporosis (, loss of bone mass and a high likelihood of fractures), especially in postmenopausal women. Having hyperthyroidism during pregnancy can lead to miscarriage, slow growth of the fetus in utero, preterm delivery and hyperthyroid crisis. Although the symptoms of abnormal thyroid function vary widely and can sometimes be misdiagnosed, a simple blood test for thyroid hormones is actually able to diagnose abnormal thyroid function. Physical examination reveals typical signs and can also provide support for a correct diagnosis. There are effective treatments for both hypothyroidism and hyperthyroidism, and we would like to help all patients.