PROBLEM TO BE SOLVED: To provide a stable complex of an alkaline earth metal salt of (6RS)- or (6S)-N-methyl-(5,6,7,8)-tetrahydrofolic acid and a polyol, and a method for producing the same.SOLUTION: There is provided a complex of an alkaline earth metal salt of N methyl tetrahydrofolic acid and a polyol produced by dissolving an alkaline earth metal salt of (6RS)- or (6S)-N-methyl-(5,6,7,8)-tetrahydrofolic acid represented by formula (1) and a polyol such as mannitol into a solvent such as ethanol and subsequently freeze-drying or spray-drying the obtained solution, where the complex is stable relative to an active component alone or a same component produced by other methods. The complex is used as a pharmaceutical preparation or a nutraceutical formulation.【課題】（６ＲＳ）－又は（６Ｓ）－Ｎ５－メチル－（５，６，７，８）－テトラヒドロ葉酸のアルカリ土類金属塩とポリオールとの安定な錯体、及びその製造法の提供。【解決手段】式（１）で表される（６ＲＳ）－又は（６Ｓ）－Ｎ５－メチル－（５，６，７，８）－テトラヒドロ葉酸のアルカリ土類金属塩とマンニトール等のポリオールをエタノール等の溶媒に溶解し、これを凍結乾燥又はスプレー乾燥することにより製造した、活性成分単独又は他の方法で製造された同一の成分に比べて安定である、Ｎメチルテトラヒドロ葉酸のアルカリ土類金属塩とポリオールとの錯体。前記錯体は医薬製剤又は栄養補助食品製剤として使用する。【選択図】なし
