Theoretically...generics are supposed to be the same level of effectiveness at the same dose as the brand name.In a lot of cases they are, or close enough. For many meds getting a really precise concentration in your blood (or whereever the drug is working) is not terribly important, and the cost savings are sometimes quite substantial.For Imodium I do not think any minor differences between the generic or the brand name will be a big deal. And most people using the generic seem just fine.Things like thyroid medications, or other meds where people have them work well at different doses (like an antidepressant or some blood pressure meds) the switch to the generic does seem to make a difference for some people, and the switch may mean needing to find the correct amount of the drug all over again.But I don't think Imodium is a big deal when it comes to a couple of percentage points difference.K.