It is understood the 42-year-old man demanded drugs when he allegedly entered the Oamaru Pharmacy with a knife around noon.
Police said "two items" were stolen in the raid on the Thames St pharmacy.
The man fled on foot and was found by police around 25 minutes later, Senior Sergeant Jason McCoy, of Waitaki, said.
“Police units were quickly mobilised in the Oamaru area. Thanks to information from members of the public and good tracking work, the alleged offender was located and arrested on Usk Street.”
Snr Sgt McCoy said the man was apprehended without incident.
"There is no place for this violent behaviour in our community, a message I hope we made clear this afternoon.
"I would like to thank members of the public who remained calm in the situation and provided information which ultimately led to a charge being laid.”
Snr Sgt McCoy said an officer was speaking to witnesses at the pharmacy to finish off inquiries.
He was facing a charge of aggravated robbery and was due to appear in the Oamaru District Court, sitting in Timaru District Court, tomorrow.
