Since high contamination by heavy metals has been found in Malaysian tongkat ali extract, there has been increased concern not just about heavy metals in Malaysian herbal supplements but also about the danger of arsenic poisoning.

Please see this page from the Malaysian Medical Resources website:

http://medicine.com.my/wp/?p=1988

A few years back, the former Malaysian Deputy Prime Minister Anwar reported that he himself suffered from unnaturally high levels of arsenic.

http://www.atimes.com/se-asia/AI14Ae02.html