Possible causes of greenish urine color: 1. When using medications such as B vitamins, it can lead to greenish urine color, or after taking large amounts of antibacterial agents. Patients who consume vitamins can experience a change in the yellow-green color of the urine, which can return to normal after stopping the intake of the relevant medication.2. When there is a urinary Pseudomonas aeruginosa infection, a greenish color of the urine can occur. This condition is mostly accompanied by signs of urinary tract irritation, such as frequent urination, urgent urination, painful urination or fever and back pain. If Pseudomonas aeruginosa is cultured in the middle urine, the diagnosis can be confirmed and anti-infection treatment is needed. 3. Patients with high bilirubin levels in the urine can have greenish urine. This is because bilirubin can appear as bilirubin after it has been left to oxidize for a period of time. Therefore, patients with elevated urine bilirubin can appear to urinate in the state of holding urine. Or the urine that is excreted can appear light green after being left for a period of time.