Milk of Magnesia, Regular Flavor, 12 oz, QC90124 Sale! This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. Compare to the Active Ingredient in Phillips Milk of Magnesia Regular Strength. Relieves occasional constipation. Generally produces bowel movement in 1/2 to 6 hours. Effective overnight relief. Stimulant and sugar free.