 (CNN) From 2005 to 2012, the rate of calls to poison control centers about dietary supplements increased by almost 50%, and most of the exposures were in children younger than 6 years old, according to a study published Monday in the Journal of Medical Toxicology . Examining nearly 275,000 reports from the National Poison Data System between 2000 and 2012, Spiller and his colleagues came up with trends and details about dietary supplement poisoning calls. At least 275,000 calls — an average of one call every 24 minutes — were made to poison control centers because of exposure to all kinds of dietary supplements between 2002-2012, according to the Center for Injury Research and Policy and the Central Ohio Poison Center, both at Nationwide Children's Hospital. The symptoms most associated with supplement ingestion included tachycardia, or rapid heart rate; vomiting; nausea; irritability; drowsiness and dizziness. Related: Caffeine Overdose Killed South Carolina Teen 
 
 The study also found that 78 percent of yohimbe exposures occurred in children, ages six or older, although most supplement exposures occur in children under six. “Lack of federal oversight has led to inconsistencies in the quality of dietary supplements, product mislabeling, and contamination with other substances,” Henry Spiller, a co-author and director of the Central Ohio Poison Center at Nationwide Children’s, said in a statement. From 1999 to 2012, the number of adults who reported using dietary supplements has remained steady in the range of 49% to 54%. Two botanicals of note that seemed particularly dangerous were yohimbe, used for male sexual enhancement, and ma huang (aka ephedra), used for boosting energy, alertness, weight loss, and athletic performance. “Our results demonstrate the need for FDA regulation of yohimbe and energy products in the US as was done successfully with ma huang products in 2004,” the authors conclude. Six deaths were associated with ma huang, three with homeopathic agents and one with yohimbe, the researchers said. The FDA said they are regulated as unapproved drugs 
 
 According to the FDA's website, the agency "regulates dietary supplements under a different set of regulations than those covering 'conventional' foods and drug products. "However, dietary supplements are not considered drugs, thus they are not required to undergo clinical trials or obtain approval from the FDA prior to sale, unless the product is labeled as intended for therapeutic use."
– A Journal of Medical Toxicology study of calls made to poison control centers over the past 12 years finds one herbal supplement to be particularly concerning. Of those calls, the ones with the biggest proportion of serious medical outcomes had to do with yohimbe tree bark extract, NBC News reports. The extract, which comes from an evergreen tree found in Africa, has been used there for centuries to treat various maladies, but it's most popular as a libido booster for both men and women—though there's little evidence of its efficacy. It can cause changes to heartbeat rhythm and even kidney failure in kids. Overall, the study found that between 2005 and 2012 there was a 49.3% increase in calls to poison control centers related to dietary supplements, including vitamins, energy drinks, homeopathic products, herbal medicines, and some hormonal treatments, Ars Technica reports. The senior author of the study notes that products classified as supplements aren't considered drugs, and thus don't go through the FDA approval process (and may not be stored in childproof containers). In the case of yohimbe, the FDA doesn't recommend its use, as it's easy to overdose. Even the recommended dosage can lead to problems such as high blood pressure and rapid heartbeat, and overdose can lead to seizures and even death. The study found 1,818 cases of yohimbe exposure reported between 2002 and 2012, 78% of them in children. Of all the cases, 512 were serious; 3.2% of patients were admitted to a critical care unit, and one died. "Sometimes, parents don't think of keeping dietary supplements away from their kids, because they're not medicines prescribed by the doctor. People think of them as natural," another lead author tells CNN. "But they need to be treated as if they were a medicine. Don't leave them out on the counter. Keep them out of reach." (This herbal "detox" sent a woman to the ER.)