Police are investigating after four people in Blackpool had an adverse reaction within a short time of one another after taking heroin.
The emergency services were called to several separate incidents on Saturday in central Blackpool.
It is not yet established whether the four incidents are linked but police are warning heroin users in Blackpool to be vigilant.
Det Insp Kirsty Wyatt of Blackpool CID, said: “We are currently investigating the source of the heroin and working closely with partners in Health.
“We would advise anyone to avoid taking illegal drugs.
"However, if anyone has taken heroin and starts to feel unwell, or experience an unusual reaction, please seek medical help immediately."
It is also advisable that users should not inject heroin when alone, so there is assistance should they suffer an adverse reaction.