Abstract: A method for preparing a solution containing water-soluble minerals comprising the steps of pulverizing and mixing starch or cereal, seed having water-soluble mineral contents and egg shell, adding water to form an aqueous mixture and agitating the same while heating to approximately 80.degree. C. to form a viscous mixture, fermenting the mixture by adding koji to the mixture, and aging the fermented mixture to cause the water-soluble mineral contents in the seed to be dissolved into the aqueous mixture and filtering the resultant fermented and aged mixture to obtain the solution of water-soluble minerals.