The structure of hydroxyethyl starch.

1. It is suggested that the structure currently used to describe hydroxyethyl starch (a blood plasma volume expander) is a gross oversimplification.2. A model having a much more complex substitution-pattern is proposed, and an accurate, rapid test has been devised for distinguishing between the two models.3. This test shows that the simple model has no basis in reality, and that the more complex substitution pattern is correct.4. Studies involving the enzymic hydrolysis of hydroxyethyl starch are shown to provide qualitative support for the new model, and the significance of the findings is discussed.