Is d-mannose (to prevent uti) safe to take in the week prior to elective surgery?

It's safe, but...: ... it probably doesn't work. Although d mannose is promoted online and in health food stores to prevent UTI, but research shows that it doesn't work -- or only slightly and only in some women. It's really not worth the money. In women with recurrent lower UTI (cystitis), simply drinking lots of fluids is more helpful. However, d mannose is entirely safe, including pre-operatively.