Fentanyl showed up in 94% of used syringes tested in Plovdiv, the Centre for Humane Policies says. The samples were collected in July and August this year at two spots in the city, and tests were run at the Military Medical Academy in Sofia.
Researchers tested 152 syringes in Plovdiv and 150 in Sofia, where fentanyl turned up in 17% of them. The Sofia samples came from three locations.
The samples are part of ESCAPE, a project run by the European Union Drugs Agency that studies residue in used syringes, and this is the first time Bulgaria has taken part. The agency says such samples show what's happening in one city among one group of people, not across the whole country.
"Our country is already a leader in the number of positive fentanyl samples," said Yulia Georgieva of the Centre for Humane Policies, who works with people struggling with addiction. She added that the centre has warned for years about the fast-rising use of fentanyl, and the study backs up those concerns.
The EU Drugs Agency recorded more than 100 fentanyl-linked deaths in Bulgaria in 2024 and 2025. These powerful synthetic opioids cause poisoning and death far more often than other drugs. The agency warns the danger is high even when someone doesn't know what's in the mix they've bought.
Naloxone, the drug used to reverse opioid overdoses, isn't easy enough to get, whether for people with addictions or for outreach workers on the street, the Centre for Humane Policies says.
Fentanyl is injected, and the group's own observations also show it being mixed with synthetic cannabinoids known as "herb" or "bonsai". How often the drug gets added to other substances without users knowing is not known.
Some of the samples were collected while police had stepped up their presence in high-risk areas, which may have affected the results.
Police from the organised crime unit GDBOP busted a fentanyl lab in Sofia in August. Fentanyl has also turned up during police raids in various Bulgarian cities in recent years.
Speaking to parliament's anti-mafia committee in July, Vincenzo Molinese, commander of the carabinieri's special operations unit, said Italy has no evidence that organised crime is behind fentanyl distribution, but the market needs watching. The hearing was prompted by the theft of 80 fentanyl ampoules from a hospital in Rome.