Every year, thousands of people end up in the emergency room for one simple reason: They make a mistake with their pain medication. So, here are a few common mistakes and how to avoid them.

First: If one pill is good, two must be better. Kristen Binaso is a spokeswoman for the American Pharmacists’ Association. She says that doubling the dose of a painkiller won’t speed up relief. In fact, with some meds, increasing the dose decreases its effectiveness. On the flip side, extra pills can cause life-threatening side effects, like stomach bleeding and perforation.

The second pain-med mistake: Taking multiple products at once. That sets you up for what doctors call duplication overdose. Bottom line: Many over-the-counter and prescription pain medications contain the same ingredients. For example, a lot of cough syrups and cold meds contain acetaminophen and taking too much can cause liver damage and according to the FDA, about 26-thousand people a year are treated for accidental overdoses of acetaminophen.

The 3rd mistake is dangerous on several fronts: Hoarding drugs “in case” they need them again. Pain specialist Dr. Eric Haynes says the compounds in many medications break down over time. Which means the pills may no longer work or may even have turned toxic and hoarding pills could tempt a family member to abuse them. According to The Partnership for a Drug Free America, 1 in 5 teens has taken prescription medications to get high.