The present invention relates to (S)-proline sulfonamide compounds of formula (I)wherein R1 and R2 are as described in the description, or pharmaceutically acceptable salts thereof, for use in the prevention or treatment of diseases or disorders related to the orexin system. The present invention also relates to the use of (S)-proline sulfonamide compounds of formula (II) as pharmaceuticals, to pharmaceutical compositions comprising compounds of formula (II), and especially their use in the prevention or treatment of diseases or disorders related to the orexin system.本發明係關於式(I)之(S)-脯胺酸磺醯胺化合物,其中R1及R2係如說明書中所述,或其醫藥學上可接受之鹽,其適用於預防或治療與食慾素系統相關之疾病或病症。本發明亦關於式(II)之(S)-脯胺酸磺醯胺化合物作為醫藥劑之用途、包含式(II)化合物之醫藥組合物及尤其其在預防或治療與食慾素系統相關之疾病或病症中的用途。