The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) has issued a health warning about the use of the herbal weight loss product Herbal Flos Lonicerae (Herbal Xenicol) Natural Weight Loss Formula due to concerns over possible side effects.

The agency is advising people not to take the pill after a patient was hospitalised and several others reported suffering from palpitations, severe gastritis and abdominal pain after taking the capsules.

The herbal formula, available over the internet and some traditional Chinese medicine outlets, is believed to contain an undeclared pharmaceutical substance and is currently undergoing laboratory testing.

MHRA head of herbal medicines policy Richard Woodfield said: “Since 2005, the MHRA has found over 280 examples where so-called herbal or natural products have been adulterated with random quantities of powerful pharmaceutical substances. Such products pose a real risk to the public.

“It is situations such as this one that the Traditional Herbal Registration scheme is being introduced and why EU legislation has been changed in order to regulate herbal medicines,” he added.