Hyperthyroidism is a condition with several signs and symptoms which can occur with variable degrees of severity. Less common than hypothyroidism (covered in an earlier article; Perry, 2025), the problem occurs in countries around the world and is more often seen in older adults. Due to the fact that some of the symptoms can mimic other conditions, diagnosis can be challenging. This article gives an overview of the disease, looking at presentation, diagnosis, treatment and complications with the aim of improving understanding of this difficult disease among nurses and nonmedical prescribers.