Immediate acting. Guaifenesin 400 mg. Expectorant. Relieves chest congestion. Thins and loosens mucus. Trust. Quality. Excellence. Questions or comments? Call 1-877-753-3935 Monday-Friday 9am-5pm EST. Other information: Store between 20-25 degrees C (68-77 degrees F). Keep outer carton for complete warnings and product information.