The penicillin molecule is a widely known molecule frequently used in the medical world to cure bacterial infections. Its chemical composition is C16H18N2O4S. It is a bodily irritant, health hazard, and environmental hazard. Its molecular weight is 334.4 g per molecule. It appears in its solid form as an amorphous white powder. Penicillin is also mildly soluble in water. 2 types of penicillin are administered, penicillin G and penicillin V, which are administered intravenously and orally, respectively. It is so effective because it interferes with bacterial cell walls to kill them individually. Penicillin was used widely to treat infections when bacterial infections were widely spread. Penicillin was the first antibiotic to be ever created in 1928 by Alexander Fleming after extracting crude material from the fungus, Penicillium rubens.