The move is based on an article in the March 2008 edition of the British Columbia Medical Journal, detailing how an adult male had symptoms of vomiting and diarrhoea, believed to have been caused due to heavy metal poisoning by consuming one tablet a day of Puspadhanva Rasa, manufactured by Shri Dhanwantri Ayurvedic Pharmacy of India.

The patient purchased the drug from India and used it over a number of years to ‘increase vigour'.

Health Canada had advised consumers in March and July 2005 and later in June and September 2006 that some Ayurvedic medicinal products may contain harmful levels of heavy metals. The campaigns were based on a study in the December 2004 issue of the Journal of the American Medical Association (JAMA) on commercially available Ayurvedic medicinal products sold in Boston.

The study had alleged that 14 of these products, made by Ayurvedic firms, like Dabur, Zandu, Baidyanath, Himalaya and Jalaram, contained harmful levels of lead, mercury and arsenic.

Based on the JAMA study, Health Canada, the UK's drug regulator MHRA and Singapore's regulator HSA had issued warning against Ayurvedic products with high metal content.

The issue also caused India's ministry of health to make heavy metal tests mandatory for herbal, Ayurvedic, Siddha and Unani medicine exports from January 1, 2006. The exported products also have to display on the label whether the heavy metals are within the permissible levels.

In its reminder to Canadian citizens, Health Canada said heavy metals may be used in a detoxified state in these medicinal products because of their presumed therapeutic properties. However, improper manufacturing processes may result in dangerously high levels of heavy metals in the final product.

Meanwhile, Ayurveda industry professionals said Puspadhanva Rasa is a prescribed drug and has to be taken under medical supervision. Heavy metals contained in Ayurveda, a time-tested therapy for many centuries, are de-toxified and would not cause any harmful effects, they added.

Health Canada says high presence of heavy metals in the body pose serious health risks because they may accumulate in vital organs to create serious health problems in a later stage.