Milk of Magnesia, Mint Flavor, 12 oz, QC90128 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. Relieves occasional constipation (irregularity). Generally produces bowel movement in 1/2 to 6 hours. Effective overnight relief. Low sodium. Stimulant and sugar free.