Whether patients with thyroid nodules can eat purple cabbage, need to be based on the functional status of the thyroid gland to decide, if the thyroid nodules combined with hyperthyroidism, it is generally not recommended to eat purple cabbage, for the other thyroid nodules, in general, you can eat purple cabbage in moderation. Thyroid nodules are divided into benign and malignant nodules. Common causes of thyroid nodules include iodine deficiency, radiation exposure, excessive iodine intake, heredity, thyroiditis, and overgrowth of normal thyroid tissue. There are also potential causative factors such as obesity and selenium deficiency. If thyroid nodules are combined with hyperthyroidism, an iodine-restricted diet is needed, i.e., consuming non-iodized salt and avoiding seafood, such as kelp and nori. For thyroid nodules with normal thyroid function, it is recommended to have an iodine-adapted diet, i.e. consume iodized salt and moderate intake of iodine-containing foods, such as kelp and nori. Patients with thyroid nodules should receive guidance from their local attending physician for a specific diet plan.