Hi: Milk of Magnesia is an osmotic laxative that works by drawing water to the colon; it is much better than stimulant laxatives like Senokot if you must use something for relief. it is called "Philips Milk of Magnesia" and is in a kind of dark blue bottle. you will find it where you find other laxatives; ask the druggist where it is. Ex lax has also come out with Milk of Magnesia and it is the same thing. It is the only thing that works for me; you cannot develop a tolerance to it like you do a stimulant laxative; I used it for 10 years and never had to increase the dosage; unfortunately I abused it by using it every day for 10 years. Don't get hooked on it; just use it when you really have to and in the meantime work on natural ways to help you; one of the things that works for alot of people on this board are magnesium supplements; anywhere from 400-1000 mg can help and it is natural and will not harm you.good luck--