Police said the man, from Dumfries and Galloway, suffered hallucinations, overheating, vomiting and a tingling in his fingers and toes after taking the so-called "Rolex" green pill.
The tablets are identical to others that have been found elsewhere in Scotland, Northumbria and Northern Ireland and have been linked to the death of at least one man. They are believed to contain little of the active ingredient of Ecstasy but instead include Paramethoxyamphetamine and Paramethoxymetamphetamine, which are known to raise blood pressure and body temperature.
Chief Inspector Mark Hollis, from Police Scotland, said: "PMMA/PMA is particularly toxic. Both dealers and users may be unaware that what they believe to be ecstasy actually contains PMMA/PMA.
"The combination of MDMA (Ecstasy) and PMA can be particularly hazardous to health and has been linked with numerous deaths world-wide."
Moira Cossar, Service Manager with Dumfries and Galloway's Specialist Drug & Alcohol Service, said: "There is clear evidence that these tablets are potentially very dangerous and can cause serious harm or death."