Abstract: A blood substitute solution and methods for its use are provided. The subject solution contains: subphysiological amounts of potassium ion, 0-10 mM magnesium ion, 70-160 mM sodium ion, 0.5-4.0 mM calcium ion, and 80-170 mM chloride ion; one or more water soluble oncotic agents; an organic carboxylic acid or salt thereof; physiological amounts of a sugar; and a blood clotting factor. The subject solution is further characterized in that it does not include a conventional biological buffer. The subject solutions find use in a variety of different applications, e.g. as blood volume expanders, and the like.