<human>:  How do I remove a red wine stain from a white shirt?
<bot>: The best way to remove a red wine stain from a white shirt is to immediately soak the stain in cold water mixed with a mild detergent. After soaking, scrub the stain gently with a soft brush or cloth before washing the shirt in the washing machine using a gentle detergent. Make sure to use cool water while washing the shirt to ensure that the stain does not set. You may also want to add a small amount of white vinegar to the wash cycle to help lift the stain.