Smoking is harmful to the kidneys. Nicotine in cigarettes can stimulate sympathetic excitation and release epinephrine and norepinephrine, which can lead to an increase in blood pressure and intraglomerular pressure, causing hemodynamic changes, which can lead to kidney injury. Smoking also leads to a decrease in nitric oxide, which weakens endothelium-dependent vasodilatation and endothelial cell hyperplasia, leading to endothelial cell dysfunction, and also leads to loss of proteinuria, causing renal function damage. Therefore, smoking is harmful to the kidneys. Smokers are advised to quit smoking so as not to jeopardize their health.