[Drug mix-ups].

We investigated drug mix-ups at a Danish hospital. We found 115 drug mix-ups among 1,554 medication errors (7%). The majority were packing mix-ups with insulin, infusion fluids and prepared syringes. The most frequent cause of name confusions was illegible handwriting. Packing mix-up occurring during routine dispensing may be prevented with bar-coding, and package mix-ups occurring in acute situations may be prevented through better package design focusing on reducing the risk of mix-ups.