If you’re still measuring your child’s liquid medication with a kitchen spoon, a new study may shock you.

Researchers at Cornell University found that the size of the spoon used to administer medicine directly affects the amount of medicine poured. According to the study, 200 students were asked to pour 5 ml of liquid medicine in different sized spoons. Students given a medium-sized spoon poured 8 percent less than recommended. When given a larger spoon, students poured an average of 12 percent too much.

Pouring a little too much cough syrup is no big deal, but that’s not the case with antibiotics, epilepsy drugs, heart medicine and other prescription medication. These drugs usually require exact dosage, and any deviation could accumulate over time, possibly leading to major problems–not to mention higher health insuranc costs–down the road.

Drugs should always be administered using a measuring syringe or dosage spoon, which are available at most pharmacies. If the product comes with a measuring cap, use that instead.