Tasmania Police is investigating an armed robbery at a chemist in Sandy Bay on Sunday afternoon.
About 2pm, the man entered the Terry White Chemist and bought flu medication.
He returned about 4.15pm and demanded prescription medication and threatened staff with a knife.
The staff member met the demands.
The man was wearing blue jeans, red scarf, black fedora hat and blue sneakers. He had a purple backpack with Simpsons cartoons on it.
Anyone with information is asked to contact police.