Three years ago, my 2-year- old son overdosed on children's pain medication.

He woke up before the rest of the family and went downstairs. He pushed a tall stool over to the kitchen counter, climbed up on the counter top, reached the third shelf of the cupboard, and found a brand-new package of an over-the-counter children's pain reliever. He ripped into the cardboard box, peeled off the bottle's protective plastic cover, opened the child-proof cap, and drank all of the flavored fluid inside.

I never imagined our little boy could reach the medication. And I didn't know that many over-the-counter medicines can be dangerous if children ingest too much.

I was reminded of my son's overdose when the Food and Drug Administration recently issued a public health advisory concerning the serious harm that can result if children take too much cold medication. The FDA warned that children under 2 should not be given cough and cold medication unless instructed to do so by a doctor. This fall, they will study the safety and effectiveness of cough and cold medicines to determine whether the benefits justify the potential risks to children.

Although the FDA's advisory does not list the particular ingredients of concern, it does provide a good opportunity to educate parents about the very common - and very serious - overdose danger of a pain-relief ingredient in many children's cold medications: acetaminophen. According to several local emergency room doctors and toxicologists, acetaminophen is far more likely than the other ingredients in cold medicines to cause serious side effects or death in cases of accidental overdose.

The medicine that my son drank was children's Motrin, not acetaminophen. Thankfully, ibuprofen - Motrin and Advil's active ingredient - does not pose the same degree of overdose danger as acetaminophen. My son was not harmed.

But what if he had ingested a bottle of children's Tylenol, or any children's pain or cold medication containing acetaminophen, and hid the packaging? Doctors said he eventually would have felt sick to his stomach and vomited, symptoms like those seen with a common stomach bug. If left untreated, he would eventually have lost his appetite, been lethargic, and suffered a second round of nausea and vomiting.

If left undetected, overdose of acetaminophen can lead to liver failure and even death. (If you have any suspicions that a child's vomiting may have been caused by an overdose of a drug, contact a doctor immediately.)

I was stunned that I'd never learned about the dangers of Tylenol overdose. I thought I was keeping my kids safe by buying medications with child-proof caps and keeping medicines out of sight. That's not enough.

More than 30,000 cases of acetaminophen overdose are reported each year to the American Association of Poison Control Centers. Here in Colorado, the Rocky Mountain Poison Center received 835 calls in 2006 for acetaminophen overdose in children 5 and under, according to Mary Hilko, public education coordinator.

In the U.S., there are more overdoses and deaths caused by acetaminophen than any other pharmaceutical agent, according to the national Poison Control Centers. Thankfully, relatively few die. Emergency room doctors are trained to recognize the symptoms of what is now a common overdose in children. Most acetaminophen overdoses are detected early, and treated with an effective antidote in time to prevent liver failure.

One of the reasons acetaminophen overdose is so common is because almost everybody has some in their cupboard. Children's preparations are flavored like bubblegum or berries, tempting kids (like mine) to taste it.

Not all overdoses are the fault of children, however. Many parents think medications sold over-the-counter don't pose much risk, and that if some medicine is good, perhaps "more is better."

A 2002 Harris International poll showed that only 19 percent of people read the label's instructions for over- the-counter medicines. Sometimes people misunderstand the label's instructions. Other times, overdoses occur when people give the medicine too often, use improper measuring devices like kitchen spoons, or substitute adult formulations or sustained-release formulations for children's formulations.

One of the most common reasons for acetaminophen poisoning is that, over a period of several days, people take several medications concurrently, such as a cold remedy and a separate medicine for pain, not knowing that each one contains acetaminophen.

Acetaminophen is extremely safe and effective when taken in proper doses. It is the more appropriate pain-relief medication for infants less than six months old, and for adults with certain medical conditions. According to every doctor I spoke with, however, ibuprofen is equally effective at reducing fever and pain when used as directed. But of the two, only acetaminophen has the potential to cause serious problems when taken incorrectly.

After our scare, I threw out every pain and cold medication containing acetaminophen in my home, and replaced them with products containing ibuprofen.

This seemed like a sensible solution, especially compared with the one proposed by the American Academy of Pediatrics Committee on Drugs. The committee's advice to pediatric physicians in 2001 was that, during every annual well-child visit, doctors should tell parents about eight specific ways that acetaminophen dosing errors may occur and endanger their child, and discuss how parents can avoid these dosing errors.

This practice would prevent many accidental acetaminophen overdoses in children, but what doctor actually has time in his busy office schedule to add a lengthy tutorial on this one drug? In fact, I wondered, why don't doctors protect their young patients from acetaminophen overdose by simply advising parents to switch to ibuprofen?

I posed this question to nine different physicians here in Denver. One of these doctors almost exclusively prescribes ibuprofen for children over six months old, but doesn't tell parents that the reason is his concern about acetaminophen overdose.

Four of the doctors said that acetaminophen is such an excellent drug, when given correctly, that parents should continue to use it. The remaining four doctors said they hadn't considered using only ibuprofen in children, but said it was a reasonable suggestion that merited discussion.

I'd like to see doctors, schools, and parenting publications advise all parents, on a regular basis, on the dangers of acetaminophen overdose and urge them to install locked medicine cabinets in their homes. We go to great lengths to keep our children safe; why not lock our medicine cabinets?

In case of overdose or poisoning, contact the Rocky Mountain Poison Center at 800-222-1222. Jackie Avner can be reached at Jackie.Avner@gmail.com.