"The 'Donald Trumps' are dangerous tablets that contain extremely high levels of MDMA and could put anyone taking these in serious harm.
"If you come across these or any other type of drug, please do not take them, for your own safety, as you can never be sure what these pills contain."
The UK warnings echo similar warnings issued by police in New Zealand, who warned NZ drug users multiple times last summer about dangerous pills in circulation.
Ahead of February's Electric Avenue festival, police in Canterbury issued a stark warning about killer drugs circulating in the scene.
Senior Sergeant Paul Robertson told the Herald at the time that police didn't want to see a repeat of last year's festival, which saw a number of people hospitalised for drug-related issues.
He also said that police were concerned about the presence of high-dose MDMA (ecstasy), and dangerous cathinones (like N-ethylpentylone and eutylone) in the New Zealand music festival scene this year.
"These substances are being distributed for profit with little regard for the wellbeing of the person consuming them.
"These substances may be offered to you in the lead-up to, or during, the Electric Avenue music festival.
"Our advice is that it is safest not to take any substance that you do not know the origins of."