An antibiotic is a substance or compound that kills bacteria or inhibits their growth. Stargate Command offered antibiotics to the Kelownans in exchange for Naquadria. (SG1: "Shadow Play")
When 80 people evacuated the Icarus Base, only minimal medical supplies were taken with them, fortunately including antibiotics which an alternate Lt. Tamara Johansen used to treat a virus that affected the crew. (SGU: "Time")