Whether a left adrenal nodule of 2.8 cm is serious or not depends on the nature of the nodule, if the adrenal nodule is benign and non-functional, it is not too serious. Benign adrenal nodules are categorized into functional and non-functional. Non-functional benign nodules, less than 3cm, do not need treatment for the time being, and can be treated surgically if the nodule grows more than 3cm during the follow-up process. Functional adrenal nodules may secrete hormones such as aldosterone and cortisol, which may cause hypertension and hypokalemia, etc. Surgery is feasible to remove the functional adrenal nodules to relieve the patient’s symptoms. Adrenal malignant nodules are characterized by rapid growth, hemorrhage and necrosis, distant metastasis, etc., which can easily endanger patients’ lives and affect their survival period, and they are more serious diseases that should be treated in time. Therefore, patients with left adrenal nodule 2.8 cm should go to the hospital in time and be treated under the guidance of doctors.