Are you referring to Alexander Fleming's discovery of penicillin? Antiseptics have been used for a long time, and they weren't really invented, different chemicals and substances were used for centuries to treat things for hundreds of years. For example, quinine derived from the bark of chinchona tree in South America (think it was Peru or something) had been use for centuries to treat malaria and was discovered around late 1800s. But even later than that, they discovered that some Chinese compound artiminisin derived from bark of wormwood tree would prove to be effective against quinine resistant forms of malaria (specifically Plasmodium falciparum). But the Chinese have been using the wormwood bark as Eastern medicine/herbal therapy against malaria for hundreds of years. But yea, I'm a little iffy on the discovery of Penicillin. We now have multi-drug resistant forms of microorganisms. Louis Pasteur probably did the most for medicine in terms of aseptic techniques, pasteurization of food products, sanitation of hospitals, extrapolate that and you have today's hospital environments and part of their diagnostic criteria.