Mixtard 30 100iu/ml 10ml VialMixtard 30 is human insulin used to treat diabetes. Diabetes mellitus is a disease where your body does not produce enough insulin to control the level of your blood sugar. Mixtard 30 is a mixture of fast acting insulin and long acting insulin. This means that it will start to lower your blood sugar about hour after you take it, and the effect will last for approximately 24 hours. How to use Mixtard 30 is for injection under the skin (subcutaneously).