Are you taking vitamin supplements?? Beta carotene, and some of the B vitamins can dye the urine dark yellow or orange even. Even some dark green veggies can darken the urine too. If you're eating a lot of processed meats .. bacon, ham, pastram, sausages ... these often contain erythorbate, a natural reddish dye.

Unless you're having symptoms of an infection, including pain and fever .. then I'm sure it's benign.

Doreen