The six men, aged between 35 and 84, were comatose when they died from complications such as infections and major organ failure.

Four other middle-aged men died in a similar way in April and May.

They had taken pills containing overly high levels of a diabetes drug, which lowered their blood sugar levels and caused symptoms such as dizziness, drowsiness and weakness.

So far, four herbal products available here - Power 1 Walnut, fake Cialis, Santi Bovine Penis Erecting Capsule and Zhong Hua Niu Bian - have been found to contain the diabetes drug glibenclamide, at levels of up to five times the maximum dose taken by diabetics.

Raids by the Health Sciences Authority (HSA) and law enforcement officers, including the police, have yielded more than 500,000 such illegal sex pills worth more than $1 million.

Since such pills first surfaced here in January, 61 men have fallen ill from taking them. A further 148 are suspected of having done so, going by the symptoms they had, although none admitted to having taken these pills.

The men were aged 21 to 97.

Despite repeated warnings from the HSA, more men have continued popping these pills, though the rate at which cases are being reported to the authority has been slowing down.

Read the full story in Saturday's edition of The Straits Times.