4 ways to avoid mistakes with liquid medicines

Claire McCarthy, MD
Claire McCarthy, MD, Faculty Editor, Harvard Health Publications

Follow me on Twitter @drClaire

Measuring liquid medication should be easy, right? You just pour out the amount you need.

It turns out, though, that it’s not so easy — and that lots of parents and caregivers do it wrong. In a study just published in the journal Pediatrics in which parents were asked to measure out some liquid doses, 84% made at least one measuring error, and 29% made a large error, measuring at least twice the prescribed dose.

So the next time you measure out some acetaminophen or amoxicillin, here are four must-dos to be sure you do it right:

1. Don’t use a spoon. Even if it says “1 teaspoon,” don’t reach for your silverware drawer. Spoons can be different sizes. Measuring spoons, the kind used for cooking and baking, are better — but unless there is an exact fill line on them, it’s easy to measure too much or too little. What you should use is a medication syringe that is widely available in pharmacies (often for free with your medication, if you ask).

2. Know your units. This is crucial, and where many people mess up. Is the dose in mL (milliliters), cc (cubic centimeters, which is the same as mL), teaspoons, tablespoons, or ounces? Unfortunately, doctors use all of these. Experts are pushing for all dosing to be in mL so that it’s standard, but for the time being it’s important to double-check and make sure you know what you are dealing with.

As most medication syringes are in mL, it’s also a good idea to be familiar with the mL in teaspoons, tablespoons, and ounces:

  • 1 teaspoon = 5 mL
  • 1 tablespoon = 15 mL
  • 1 ounce = 30 mL

3. Check your math. The researchers also found that errors happened when people had to do some math to figure out a measurement, such as when a dose was 7 mL but they only had a 5 mL syringe. They found it worked out better if the parent had a 10 mL syringe… but if you do have to divide up the dose into two portions, double-check that you are doing it right. There’s nothing like the sleep deprivation involved in having an ill child to mess up your ability to add correctly.

Another thing to watch for: placement of decimal points. For example, if a parent gives 5 mL when the dose is .5 mL, that’s giving 10 times the dose. Doctors are encouraged to write 0.5 mL rather than .5 mL to draw attention to that decimal point, but not all of them do, and not all parents realize it’s there.

4. Get in the habit of clarifying the dose when you get or pick up the prescription. Just take that extra moment and ask, “So exactly how much do I give?” Ask for a syringe. (You can even ask to have someone mark the dose on the syringe.) Make sure there isn’t a hidden decimal point there somewhere, too. It takes less than a minute to do. If you make it a habit to ask every time, it could make all the difference — and help keep your child healthy and safe.


  1. Scott Conklin

    Very informative and well written article! As a leading manufacturer of safe and accurate oral dosing devices, Comar has aligned ourselves with several of the leading industry regulators and consumer safety advocacy groups to be on the fore front of best practices. We are able to custom print our oral syringes, dosage cups, and dosage spoons with the exact calibration that appears on the instructions. Printing is preferred because it is more easily recognized compared to an embossed or molded line. We have also been advocating our customers keep up with the mL only initiative per the NCPDP white paper. Please check out the “industry news” section of our website for more best practices in addition to those listed above!