What unit of measurement is commonly used to express medication dosage for liquids?

Milligrams per milliliter is the correct choice for expressing medication dosage for liquids because it defines the concentration of the medication within the liquid. This measurement helps ensure that the healthcare provider administers the correct dose of the medication based on the patient's needs. Each milliliter of the liquid contains a specific number of milligrams of the active ingredient, allowing for accurate dosing when the medication is prepared and dispensed.

Using milliliters per hour is more related to flow rates, often seen in the context of intravenous medication administration, rather than a direct dosage for liquids. Grams per liter is a measure that is typically used for larger volumes and might not be precise enough for the exact dosing needed in most medication administration scenarios. Units per tablet generally applies to solid dosage forms rather than liquids, since it indicates the amount of medication in discrete tablet forms rather than a solution or suspension.