Oamaru woman Linda Forbes hopes local youth will stay away from synthetic drugs, after a successful protest was held on Saturday.
Mrs Forbes, who organised the protest, was joined by Waitaki District Mayor Alex Familton and about 30 other people, who showed their disgust at the sale of legal synthetic drugs.
With a legal high that mimics the effects of cannabis, the synthetic drug is believed to be on sale in at least three Oamaru outlets.
Her actions come after Meadowbank Dairy staff were allegedly robbed at knifepoint this month and in a separate incident in May, and robbers took off with synthetic cannabis products.
Mrs Forbes said she hopes to see the products banned in Oamaru.
"There are a lot of people that don't know about these things," she said.
"We need to make people aware."
Mrs Forbes said she joined Mr Familton in warning local dairy owners about the damaging affects the legal drugs can have.
The response from those driving and walking past the protesters was positive, she said.
"We got heaps of toots from people and lots of thumbs up," she said. "It was really positive."
Mr Familton said the shopkeepers need to understand consequences the chemicals can have on youth.
"Regardless of the legality of them, they are destructive for young, vulnerable people," he said. Messages on placards included "Don't sit on your hands and let our youth die from legal highs" and "Legal highs wreck lives".
Mrs Forbes said the legal drugs almost tore her family apart and it was a re-occurring trend amongst other families she spoke to.
"I was talking to one woman who lost her son-in-law two years ago from this," she said.
Mrs Forbes is keeping hold of the signs, in case there is a future protest.
For updates see her Facebook page: "Help stop legal highs".