This work focuses on the determination of inositol in drugs and food supplements using high-performance liquid chromatography in HILIC mode. The work is divided into several sections, it discusses the characteristics of analyzed myo-inositol including methods for saccharides determination. A chapter is detached for high-performance liquid chromatography. One of the work goals was also chromatography columns comparison. The experimental part includes measurement conditions, methods of sample preparation evaluated data and results including the discussion. Two real samples were analyzed, in both of them the content of myo-inositol was declared by the producer.