Yet informing health-care providers about vitamins, herbal and homeopathic remedies is important because in some cases they can adversely interact with traditional medications, the researchers say.
In a survey of parents having their children treated at two Canadian pediatric hospitals, researchers found that alternative medicines and such therapies as massage and chiropractic were commonly used.
At Stollery Children's Hospital in Edmonton, 71 per cent of parents surveyed said they treated their kids with complementary medicine, while 42 per cent of parents attending the Children's Hospital of Eastern Ontario (CHEO) in Ottawa reported their use.
"Our study found that many, many children use complementary therapies, and unfortunately oftentimes parents do not necessarily disclose this use when they're talking to their child's health-care team," said pediatrician Dr. Sunita Vohra, co-principal author of the study.
The research, published Monday in the journal Pediatrics, found almost 20 per cent of families surveyed said they had not told their physician or pharmacist about using both prescription and alternative medicines together.
"The reasons for this are probably many and varied," Vohra said from Edmonton. "Sometimes, parents don't feel comfortable bringing it up. Sometimes, they're not sure how that information is going to be received by the health-care team."
And in other cases, parents may not think the information is relevant because they may not consider a herbal remedy, for instance, as being a medicine, she said.
The study involved a total of 926 families at 10 different clinics in Edmonton and Ottawa, with parents asked to fill out an anonymous questionnaire in the waiting room prior to their child's appointment.
The young patients were being seen at clinics in the two hospitals that deal with pediatric cardiology, gastroenterology, neurology, oncology and respiratory health conditions.
The most common complementary medicines used were multivitamins or minerals, herbal products and homeopathic remedies, while the most often-used alternative therapies were massage, chiropractic, relaxation and aromatherapy.
Almost half reported using forms of complementary remedies at the same time as being treated by conventional medicine, while about five per cent said they used such alternative therapies instead of standard medicine.
Parents were two to three times more likely to use complementary medicine if their child's health was fair or poor and if the parent used that form of treatment themselves.
The study also found that about 56 per cent of respondents were treating their youngsters with alternative forms of medication at the same time as they were taking prescription drugs.
But such concurrent treatment can be risky: the study found 80 cases of interactions between complementary remedies and traditional drugs, including 19 considered moderately adverse and six that were deemed severe.
Fish oil, for instance, can cause the blood to thin. Combining it with a pharmaceutical blood thinner can result in bleeding, Vohra said.
Echinacea, a herb taken by many people to boost the immune system, can counter the effectiveness of chemotherapy used to treat cancer, she said.
"There's all kinds of medications that can interact and you have to (assess) it on a case-by-case basis," noted CHEO pediatrician Dr. James King, who led the study with Vohra.
"The big thing is if you don't ask about it, you don't know to check, right?" King said from Ottawa.
"And if it's possible that 20 per cent of your patients are coming in and they are on medications and they're not disclosing this (alternative) treatment ... on our side as a profession we need to make sure that we're asking."
Vohra also cautioned that "more is not necessarily better."
"We have seen patients that have gotten into trouble if they expose themselves ... to polypharmacy —the idea of taking many things at the same time," she said. "Even though the things they're taking are natural health products, if you're on a long list of them, I would be careful.
"People make an assumption that natural means safe."
The study also found that more than 60 per cent of parents reported getting information about complementary medicine from "family." Others cited the Internet, health food stores, pharmacies, and books and magazines.
"They get their information from a variety of sources, and when you have a commercial interest, when someone is trying to sell you something, you may not actually be getting an unbiased source of advice," Vohra said.
"So we think it's useful to try to create an opportunity for dialogue where there isn't a sales pitch attached to it," she said, encouraging parents to raise the issue of complementary medicine use with their child's care providers.
King said the study suggests that families want doctors and other health providers to ask about the use of complementary medicine, and they want a reliable source of information about their potential benefits and harms.
"A lot of people are using it," he said. "I think we need to recognize that and we just need to build it into our care plan."