Lethal horse drugs were stolen during a burglary at a veterinary surgery in south Shropshire.
Sedatives and drugs used for putting horses down were taken from the Old Pound Veterinary Equestrian Centre in Aston Munslow, near Craven Arms.
West Mercia Police said the break-in happened overnight on Wednesday.
Anyone who finds the drugs, which can be lethal for humans in small doses, is urged to discard them or hand them in to a chemist or police.
Two brown bottles of Somulose were stolen, police said.
Pc Ingrid Hall, investigating, added: "This is a clear liquid used for putting horses down and could prove lethal to humans, even in small quantities."
She said the bottles were about an inch long, had a rubber top and a white and red label.
A quantity of Ketamine and Diazepan was also stolen in the burglary. Police said these drugs could also be fatal for humans.