Police are carrying out surveillance on a farmer's fields after drug users began stealing legally-grown hemp plants in the mistaken belief they were cannabis.
Thieves are stealing the plants believing they are cannabis
One person has been charged with theft and there have been reports of others digging up the plants in the dead of night and using the leaves in cigarettes.
Local residents have also confused the plants with cannabis and have tipped off police about the presence of the "drug".
But police have reassured them the crop is being grown legally under licence.
They say hemp contains very low levels of cannabis and has virtually no psychoactive effects when consumed.
Hemp has a variety of industrial uses including making paper, textiles, food, clothes and medicine.
West Mercia Police are not identifying the exact location of the fields.
But they admit they are carrying out police patrols and will take action against anyone caught in the fields.
Acting Chief Inspector Jim Baker confirmed one person had been arrested in connection with theft of the plants.
He told BBC News Online: "We have received some calls from members of the public who are concerned that this drug is being grown as many people confuse it with cannabis.
"I want to reassure people that this plant is being grown legally and under licence.
"It is not cannabis, if smoked it will have no effect and will not cause any harm.
Distribution of drugs
"Because it can be confused with cannabis it appears that some people have been helping themselves to the plant.
"We want to tell members of the local drug community that there is no point stealing it.
"You won't get high on it.
"It's no good for smoking.
"It is a controlled drug and we would advise people to stay away from the fields."
Inspector Baker confirmed that one man had been charged with theft and several others had been caught trying to steal the hemp plants.
He said: "The other night there were four local youths stopped with bags full of the stuff.
"We shall be carrying out patrols in the area and action will be taken if people are caught in the fields.
"We will not tolerate the use of drugs in area and we welcome any information about the use or distribution of drugs."