The optical activity of glucose molecules is important for diagnosing and monitoring blood glucose of diabetes. In order to accurately detect the diabetes at an early stage, there is an urgent need to develop innovative detection methods. By use of Mueller matrix decomposition (MMD), we have studied the optical activity of glucose molecules in three types of turbid media—polystyrene (PST) sphere suspension, chicken blood, and the vein blood of diabetic patients. The experimental setup to obtain the Mueller matrix in the forward detection geometry has been used. The experimental results show that the rotation angle has linear relationship with the concentration of the glucose when the scattering coefficient of the PST sphere suspension remains unchanged, whereas the scattering effect enlarges the rotation angle. Furthermore, optical rotation abides by Drude’s dispersion equation. The decomposition method has also been found useful applications in quantifying the optical rotations of blood glucose in diabetic patients. The diabetic severity status can be distinguished with the rotation angle of glucose and also is in accordance with the clinical diagnosis. Thus, the method of MMD has promising applications in diabetic diagnosis and monitoring.