Instructions. Hydrate. Drink plenty of water regularly. This will help to flush bacteria out of your urethra, urinary tract and bladder. Drink cranberry juice. Cranberry juice works as a natural antibiotic, helping to clear bacteria and infection from your kidneys and urinary tract.Choose wholly natural cranberry juice, rather than mixed varieties. Try cranberry capsules.nstructions. Hydrate. Drink plenty of water regularly. This will help to flush bacteria out of your urethra, urinary tract and bladder. Drink cranberry juice. Cranberry juice works as a natural antibiotic, helping to clear bacteria and infection from your kidneys and urinary tract.