An injecting drug user who died earlier this week has tested positive for anthrax, health officials have said.
The middle-aged man died in Glasgow on Sunday.
Contaminated heroin, or a contaminated cutting agent mixed with the drug, may have been responsible for his death, officials said.
NHS Greater Glasgow and Clyde said it was an isolated case in the city, and police are now investigating.
The death was confirmed by the health board's Public Health Protection Unit (PHPU).
Public health consultant Dr Syed Ahmed said: "This is an isolated case in Glasgow and there have been other sporadic cases in the UK and Europe in recent months. We are working with other services and colleagues to be on the lookout for any other possible cases, especially amongst other injecting drug users.
"Drug injecting is extremely risky and dangerous. I urge all drug-injecting heroin users to be extremely alert and to seek urgent medical advice if they experience an infection at the site of injection."
Anthrax is a bacterial infection and is primarily a disease of herbivorous mammals, though other animals and some birds can also get infected. Drug users can be exposed when heroin is contaminated with anthrax spores.
While injecting drug users need to be on their guard, the risk to the rest of the population is negligible, officials said.
It is rare for anthrax to be spread from person to person and there is said to be no significant risk of airborne transmission from one person to another.
The PHPU is now working with Strathclyde Police to identify a possible source of the infection.