A thyroid nodule is a nodule that grows in the thyroid gland in front of the larynx. What is meant by a diffuse thyroid nodule is mainly an ultrasound finding of multiple nodules of varying sizes and relatively similar diameters in the thyroid gland bilaterally, which is called a diffuse thyroid nodule. Diffuse thyroid nodules are commonly associated with diseases, mainly chronic lymphocytic goiter, which can be called Hashimoto’s disease. Once a diffuse thyroid nodule is present, it is best to have an ultrasound and a thyroid function test. If the nodule is large or if secondary hyperthyroidism is present, surgery may be required. If the nodule is large or secondary hyperthyroidism is present, surgery may be required. However, in the absence of these symptoms, the nodule can be treated conservatively with ultrasound to monitor changes in the thyroid gland regularly and a small amount of Eugenol if necessary to reduce the nodule’s further expansion.