A potentially lethal batch of ecstasy pills are in circulation in the UK.
The orange tablets are in the shape of a shield and stamped with an image similar to the Dutch Republic Lion.
Police have put out a warning after two clubbers died in Liverpool on Boxing Day and five more were hospitalised in Birmingham over New Year.
Some users believe they are counterfeit versions of high strength pills with the same design (manufacturers regularly copy strong pills to capitalise on their popularity).
John Milburn, 19, and Andy Glaister, 47, both died after falling ill at the closing night of Liverpool party Cream at Nation on Boxing Day.
It is suspected that both men took the contaminated pills, with a post-mortem due to take place.
Detective Chief Inspector Andy Ephgrave of Merseyside Police said: "At this stage of the investigation, we are exploring a number of lines of inquiry and it is unclear if both men took illegal substances.
"We are continuing our investigations today but would like to take this opportunity to remind people of the dangers of taking illegal drugs.
A further four men and one woman were hospitalised in Birmingham after taking the pills in the Rainbow nightclub across New Year's Eve and New Year's Day.
It was reported on Saturday that one of the men was fighting for his life in a critical condition.
Police have urged anyone who has taken the drug to exercise extreme caution and dial 999 if they begin to feel unwell.