Anisotropic structures, such as fibers, are highly important components of skin, providing functions such as strength, elasticity, and protection. They are sensitive to polarized light, and their polarization response characteristics can be expressed by Mueller matrix which could be measured by the changes of the polarization states of light. Mueller-matrix optical coherence tomography and Mueller-matrix polarimetry are two typical label-free techniques that can acquire cross-sectional Mueller matrices and surface Mueller matrices of tissues. By using these two methods, the polarization information of normal skin, malignant melanoma, malignant lentigo, etc. can be analyzed and compared with their pathological results. The sensitivities of different polarization parameters of the skin can be studied in order to find some specific ones that can better assist clinical diagnosis.