A man threatened with a knife staff at the Co-operative Pharmacy on Monks Road and demanded Diazepam, at about 3.10pm on Thursday, June 24th.
Diazepam is a drug commonly used for treating anxiety, insomnia, or seizures. The robber put the drugs into a weaved-type carrier bag he had with him.
The offender is described as wearing dark glasses, a tea-cosy type hat, and what is thought to be a black and red streaked wig.
He was also wearing a black coat and blue surgical gloves. No-one in the chemist was injured in the robbery. Police conducted an area search and enquiries continue.
Anyone who was in Monks Road area near the Co-operative chemist during the time of the incident, and saw anyone similar to the description, is asked to contact Lincolnshire Police in confidence on 0300 111 0300.