To : Ilene Re : Fluorescein Dye Now this is really rare. Fluorescein when used IV may produce changes in color of milk, maternal skin, and possibly changes in taste sensation(bad). Urine is fluorescent for up to 36 hours. I would also suggest a brief waiting period of pumping and dumping, but 72 hours seems a little excessive. Perhaps 36-48 hours at most. The mom could observe her milk for fluorscence. Regards Tom Hale