The fluorinated pyrimidine anticancer agent has several side effects that degrade the quality of life of patients, including hyperpigmentation. Hyperpigmentation differs in color from common pigmentation such as a suntan, giving rise to dramatic skin appearance changes. In this study, we measured the optical properties of the skin of patients with hyperpigmentation by using the reflection spatial profile method (RSPM). The absorption coefficient in hyperpigmentation increased ~1.5-2.5 times and pheomelanin significantly increased compared to the normal skin. In addition, the scattering coefficient of skin with hyperpigmentation was about 65.9-76.5% of that of normal skin.