Hematuria is relatively specific for a genitourinary disorder, but patients who report red urine may instead have one of the following: Myoglobinuria Hemoglobinuria Porphyrinuria Porphobilinuria Food-induced urine coloring (some foods, eg, beets, rhubarb, sometimes food coloring, may make urine appear red) Drug-induced urine coloring (some drugs, most commonly phenazopyridine, but sometimes cascara, diphenylhydantoin, rifampin, methyldopa, phenacetin, phenindione, phenolphthalein, phenothiazines, and senna may make urine appear dark yellow to orange or red) High concentrations of urinary protein cause frothy or sudsy urine.