A man was admitted to hospital after it is believed he took a legal high in Spalding.
Police were alerted to the incident at just before midday today.
The man has since been released from Pilgrim Hospital in Boston, but police are keen to trace another man who may have taken the same substance.
Information suggests that the legal high that has been taken is called ‘Sensei’ and was purchased from a shop in Boston.
There have been a number of similar reports recently with people having taken this drug being admitted to hospital.
There is clearly a risk to the health of individuals taking this substance and police would urge anybody with any information in regard to the use or supply to contact them and to refrain from using this substance.
If you have any information, call police on 101.