if penicillin hadn't been discovered

penicillin is one of the first medical antibiotics, it's efficiency and effectiveness against bacteria is proof that penicillin is important.
if penicillin hadn't be discovered millions of people would have been died because of bacterial infection. there is two kind of bacteria, good one and bad one. good bacteria helps your digestion system, such as E-COLI, but bad bacteria messes with your immune system and makes you sick. penicillin helps your immune system to fight those bacteria, when your immune system fighting a bacteria you got a fever, which is not pleasant.
if penicillin hadn't be discovered millions of people will be dead because of bacterial infection.