The present invention provides a composition for improving glucose
tolerance to patients having diabetic hyperglycemia and people having
pre-diabetes, i.e., abnormal glucose tolerance. The composition helps
control the blood glucose level, prevents diabetic complications, and can
be administered over a long term due to its high safety. The composition
containing a coenzyme Q, in particular, a reduced coenzyme Q.sub.10, as
the main component improves the impaired glucose tolerance of diabetes
patients, satisfactorily controls the blood glucose level, and decreases
the blood glycosylated hemoglobin level.
