High creatinine may lead to foamy urine. Blood creatinine is excreted from the body primarily by glomerular filtration, and a marked increase in creatinine can occur when damage to the renal parenchyma occurs, resulting in a decrease in the glomerular filtration rate of up to 1/3 of normal. Foamy urine is usually seen in proteinuria, i.e., high protein content in the urine. Glomerular filtration of primary urine contains small molecules of protein, albumin and immunoglobulin, etc. More than 95% of the protein in primary urine is reabsorbed by the proximal tubule, and under normal circumstances, the urine contains only a very small amount of protein, which does not cause foamy urine. When creatinine is high, renal function is impaired, glomerular filtration rate decreases, and more protein enters the final urine, forming proteinuria or foamy urine. When there is high creatinine, or foamy urine, it is recommended to consult a regular hospital in time to make a clear diagnosis and follow the doctor’s instructions for treatment.