Class B drugs were found in the possession of a man at Grantham police station after he had been arrested for stealing a can of cider.
Lee Dwyer, of no fixed address, had on him two bags of a white powder which tests discovered to be methylethylcathinone, more commonly known as M-Cat.
Daniel Pietryka, prosecuting, said: “He told officers it was all his own personal drugs and for his own personal use.”
Dwyer, 31, also told officers he was not aware the drug was illegal.
Rob Arthur, defending, said M-Cat was only made illegal around 18 months ago having commonly been used as a plant fertiliser.
He added: “At the time he was homeless and he still is. He took it to help him sleep at night.
“When you are out on the street, it is not a pleasant place to be.”
Dwyer admitted possession of Class B drugs. He was fined £65 and ordered to pay £85 costs and a £20 surcharge.