Detectives circulated a warning to teaching staff and parents back in March after synthetic cannabis was found in sweets at a school in the county.
Over the previous month the force said it had come across two incidents involving young people taking ‘sweets’ which contain cannabis or spice (a new psychoactive substance).
Spice mimics the effects of cannabis, but some experts say it can be up to 100 times as potent.
Detective Chief Inspector Steve Knubley told The Standard: “Incidents involving these ‘drugs sweets’ are extremely rare in Lincolnshire.
“On this occasion after becoming aware of two incidents, we sent advice to schools asking that parents remain vigilant.
“In the first incident, on March 16, a Lincolnshire school pupil became ill after eating one of these ‘sweets’. No arrests have been made.”
The schoolboy was placed on a drip to aid his recovery.
DCI Knubley added: “The second incident took place on March 21. A man in his 20s was arrested in Skegness on suspicion of possession with intent to supply and was released under investigation.
“Since that time there have been no further reported incidents involving these ‘sweets’ in the county.
“We would always urge people to be vigilant and report anything suspicious to us by calling 101.”
The sweets are generally manufactured abroad and purchased on the internet.
DCI Knubley added in his warning: “We believe the packets are sold for around £5 and may look like the ones pictured – which look similar to a bag of Haribo and clearly producers are marketing these to young people.
“We also have information to suggest social media may be being used to advertise the drugs.”
Nick Law, headteacher at Carres Grammar School said it and Kesteven and Sleaford High School issued the warnings last term but had had no known cases.