Grains of Spiritual Life are a healing item in Ninja Gaiden II. They replace the Great Spirit Elixir found in Ninja Gaiden. They restore a moderate amount of health. This item is found in chests and can be bought at Muramasa's Shop for 4000 yellow essence in Path of the Acolyte and 5000 yellow essence in Path of the Warrior. Ryu can carry three of them at a time.
Quoted directly from game: "Grains of Spiritual Life: An extremely powerful medication that heals the body. These small grains of medicine contain a potent formula consisting primarily of two ingredients: the rare Herb of Spiritual Life mixed with the even rarer powder of Dragon's bones. The powdered Dragon bone is a catalyst, reacting with the other ingredients to dramatically increase the potency of the medication, giving it a healing effect several times greater than the Herb of Spiritual Life alone.
This medicine is also known as "Spiritual Horai Grains" in some circles. Mount Horai is a mythical mountain where hermits were said to live. These hermits devoted all of their time to unlocking the secret of immortality, and it is suggested that this medicine represents the outcome of their alchemy."