Toxic “mad honey” reaches global online markets, researchers warn

A honey traditionally harvested in Nepal is being sold through international online platforms despite containing a plant toxin that can cause a life-threatening drop in heart rate and blood pressure, according to reporting published by Phys.org. Known as “mad honey,” the product is made by Himalayan cliff bees, or Apis laboriosa. The bees collect nectar from rhododendron flowers, which contain grayanotoxin. That toxin becomes concentrated in the honey while apparently leaving the bees unaffected. The effects on people depend on the batch, season and location. The source report says a small amount may cause warmth and lightheadedness, while more than a few tablespoons can push the heart rate to dangerous levels. Symptoms often begin within 30 to 60 minutes and can include dizziness, nausea and weakness. Researchers reviewed 27 published papers covering 68 patients from 2009 onward, using records dating from 1976 to 2026. About 72% of the patients were middle-aged men, and most had consumed the honey intentionally. Reported reasons included using it as a traditional remedy for high blood pressure or to improve sexual function. The researchers found that cases rose sharply in spring, when rhododendrons bloom and the main honey harvest occurs. Honey collected during that period has the highest toxin concentrations reported in the source material. A smaller increase occurred during the autumn harvest. In one case, two people became ill after eating honey from the same batch. Treatment generally involves intravenous fluids and atropine, a drug used to restore a normal heart rhythm. Most patients recover within one or two days, and the review found no reported deaths in Nepal. However, cases have also been documented outside the country, including 15 linked to Nepali honey in South Korea in 2013 and more recent cases in France and Qatar. The source report says online sellers sometimes promote mad honey as a psychoactive product or “superfood,” with prices reaching several hundred U.S. dollars per kilogram. Warnings about safe consumption are not always provided, and buyers in other countries may not recognize the product as a possible cause of cardiac poisoning. That unfamiliarity can delay diagnosis when patients do not mention eating it. The researchers plan to test samples from different regions and seasons in Nepal to measure toxin levels. They also want to study how the cliff bee tolerates grayanotoxin. The bee itself is reportedly declining because of overharvesting, habitat destruction and climate change.