One solid preparation of the present invention has fine silicon particles as a principal component thereof, and exhibits a hydrogen generation capacity. In addition, one embodiment of this solid preparation has fine silicon particles which for the most part have a crystallite size of 1-100nm, inclusive, as a principal component thereof, and exhibits a hydrogen generation capacity of 3ml/g or higher upon contact with a water-containing solution having a pH value of 7 or higher. According to this solid preparation, hydrogen is generated when fine silicon particles contact a water-containing solution having a pH value of 7 or higher. Consequently, by taking advantage of these properties, it is possible, for example, to promote hydrogen generation in a region of the digestive tract where the pH value is 7 or higher as a result of pancreatic fluid secretion following oral administration of said preparation and passage thereof through the stomach.
