The pair entered the store in the 9600-block of Milwaukee Avenue around 7:30 a.m. Police said they took over-the-counter medication from a shelf and hid them in bags they brought with them.
When they tried to leave the store, an employee approached and told them to put the merchandise down. Police said that's when the man pulled out a hypodermic needle, pointed it at the worker and said, "You don't want what I have."
The pair left the store and got into a light-colored vehicle. Police said they got away with about $600 in over-the-counter meds.
The man was about 5 ft. 5 in. - 5 ft. 9 in. tall, weighed around 155-175 pounds and had dark hair. He was wearing sunglasses, a dark jacket and dark pants.
The woman was about 5 ft. 5 in. - 5 ft. 9 in. tall, weighed around 135-145 pounds and had light hair. She was wearing a baseball cap, a two-tone jacket and tan pants.
An investigation is underway. No one is in custody.
A similar robbery occurred in southwest suburban Naperville earlier this week, where a robber claimed to have a needle infected with HIV.