Most of the cysts in the left kidney are benign simple kidney cysts, patients do not need to worry too much, what needs to be noted is to regularly review the kidney ultrasound every year to dynamically observe the changes of kidney cysts. If the diameter of kidney cyst is within 4cm, patients without high blood pressure and frequent symptoms such as back pain do not need to take medication, they only need to pay attention to not drinking coffee, functional drinks, strong tea and other caffeine-rich drinks in daily life to avoid stimulating the cyst and make the cyst increase faster.