But you should always talk to your doctor before taking it. While "some people who use [lactase enzymes] claim they need to continue increasing their dose over time, this is more likely due to aging, ...

Lactase 1250Units; per 5 drops; liq. Add 5–15 drops to quart of milk; hydrolyzes 70%–99% of lactose at refrigerator temperature in 24 hours.

The U.S. Food and Drug Administration (FDA) recently issued a Class I recall—the highest level of alert—for several variations of Lactaid Milk due to the risk of undeclared almonds.