Authorities say it happened on April 20 around 8:00 pm at the Walgreens on North West Avenue.
Surveillance video released by police shows the suspect jumping over the pharmacy counter.
Police say the man threatened to hurt one of the technicians if she didn't open a safe holding promethazine.
He left the scene with different kinds of prescribed medicine and was last seen in the parking lot.
If you have any information, you are asked to contact the Fresno Police Department at (559)-547-6833.