How Does Penicillin Work?

Millions of lives were lost before penicillin has finally been discovered! People go as far as saying that the discovery of Penicillin has actually changed the face of medicine and the way that we see and act upon different health issues and problems and that is entirely true! You probably know that Penicillin is defined as an antibiotic but did you know the fact that Penicillin was actually the first antibiotic ever used in medicine? And you probably have heard about Penicillin being discovered accidentally, but do you know what actually has happened?

The answers to these and many other interesting questions you will find in today’s article as we unravel the mysteries that are hidden behind the discovery of penicillin and the eventual progress of medicine once and for all! But most importantly, we are here to discuss the mechanism of the act of penicillin and how exactly does penicillin kill off thousands of different bacteria in order to improve our health and free us off all those annoying symptoms. Stay with us to get all of the details!

What is penicillin?

Penicillin is the first antibiotic known to man. Penicillin is actually not only one single antibiotic – it is a group of antibiotics with strong abilities to kill off different kinds of bacteria. It is an antibiotic that is taken orally and which is found to be helpful in numerous occasions against numerous different types of bacteria such as Streptococci (especially Streptoccoci pneumoniae), Listeria, Shigella, Salmonella, H.influenze, Clostridium and many, many others. Because of its strong antibiotic properties, penicillin has so far saved thousands of patients in their battle against middle ear, sinus, bladder, kidney infections as well as pneumonia, sepsis, gonorrhea, meningitis, endocarditis, and other serious and potentially life-threatening infections, infections which in the past, before the discovery of penicillin have won these battles and ended so many innocent lives.

Penicillin is taken with or without food, as instructed by the doctor. Penicillin must be prescribed – there is no possibility for penicillin to be given over-the-counter so you must have your doctor’s prescription in order to use penicillin.

The history of penicillin

It was somewhere in the middle of London in 1928 when Dr. Alexander Fleming came back to his laboratory and found himself amazed by what he saw there that day. What he discovered was the presence of a mold known as Penicillium notatum right there in one of this Petri dishes making a clear range of the mold itself and the bacteria – staphylococci in the dish. After putting the Petri dish under a microscope, he was fascinated by the finding that that single mold has prevented the further growth of the bacteria! It took him several more weeks in order to redo the experiment a few more times before he had clear results about this exceptional finding.

When he first presented his findings to the people, they were amazed as well. But it did not take long until they tried the effects of the Penicillium notatum and confirmed the results themselves. From that day on, the numbers of cases lost due to gonorrhea and pneumonia as well as other potentially life-threatening bacterial infections to drop. It was in the middle of 1940s, that the first clinical trials have been made, and the wounded soldiers from World War Two were treated with the use of penicillin as the world’s first antibiotic ever! Later on, Dr. Alexander Fleming came to report that on that single day – September 28th, 1928, he woke up and never thought that would be the day when he would make an amazing, life-changing discovery that will save thousands of lives in the years to come. The truth is that he never once thought that he would be the man that would change the face of medicine, as it is said numerous times although that is what most scientists dream of. Thanks to Dr. Fleming, now we have something huge to rely on when it comes to killing off harmful bacteria and changing our lives.

How does penicillin actually work?

In order to understand how penicillin works, first we have to discuss the unique structure of the bacteria. Each bacteria contains cytoplasm, nucleoid, and organelles, all well protected in a capsule and a cell wall. In that cell wall, a substance known as peptidoglycan is present. The peptidoglycan is composed of sugars and polypeptides that together, form a strong, hard lattice that surrounds the cell wall, making it highly durable and strong. Not only that – the peptidoglycans also make sure that the external fluids stay as far as away as possible from the inside of the bacteria so that no changes in the osmotic pressure would occur that would eventually cause the bacteria to burst and die.

This is where penicillin comes in hand, causing everything that we have mentioned before to actually happen! It has been discovered that penicillin has the ability to damage the peptidoglycan and with that to weaken the cell wall so that there would be changes in the osmotic pressure which will eventually cause the bacterial cell to burst open and die. What penicillin does is damage the peptidoglycan so that a hole is created, however, because the penicillin damages the link in the peptidoglycan, the bacteria are unable to undo the damage and recover. In that time, water rushes through the hole and into the bacteria, causing internal damages so that the bacteria would burst.

It is important to remember that the peptidoglycan is present only in the wall cell of the bacteria and it is not found in the walls of the human cells. This makes it impossible for the human cells to get damaged by the presence of penicillin in the body which means that penicillin is actually selectively toxic and does not harm our own cells.

Is penicillin safe?

As any other antibiotic, penicillin has some potential side-effects of which the patient should be warned, although, penicillin generally is classified as a safe antibiotic. Common side effects of penicillin include diarrhea, dizziness, nausea, vomiting, insomnia, abdominal pain, bleeding, skin rash and many others which are all listed on the instructions that come with each packaging of penicillin. Your doctor will warn you about the most common possible side effects and it will be your job to remember them and report their occurrence to the doctor as soon as possible as to avoid any additional complications. Other than the possible side effects, an allergic reaction to penicillin is also possible.

Unfortunately, not all people are able to receive penicillin without experiencing something more than the usual side effects. A penicillin allergy is, unfortunately, a common complication that results in the occurrence of hives, itching, fever, swelling, and skin rash among other characteristic symptoms. These symptoms develop as a result of the abnormal reaction of your immune system to the presence of penicillin in your body. The important thing is once again, to notice the symptoms and inform your doctor as well as, remembering the fact that you are allergic to penicillin so that you will be able to avoid experiencing these symptoms ever again in the future. Other than that, penicillin is reported to be a safe antibiotic that has more positive than negative effects and we should be thankful for its existence.


We can say that the beginnings of modern medicine, as we know it today, have started with the discovery of penicillin back in 1928 by the famous Dr. Alexander Fleming. His masterpiece found accidentally in his laboratory has changed the face of medicine from day one and we should be thankful about it every day. If you think about it – penicillin has gradually reduced the numbers of innocent victims of gonorrhea, meningitis, endocarditis, rheumatic fever and so many other potentially life-threatening bacterial infections. In today’s article we have discussed the history of this famous antibiotic – the first antibiotic even, actually that has helped to save millions of lives all around the world. And how exactly? Penicillin has found a unique way to damage and kill of potentially life-threatening bacteria and that is by damaging the wall of their cell that is meant to protect them from any harm.

The unique mechanism of penicillin has abled this strong antibiotic to save our lives by quickly damaging the bacteria and kill them off in only a few days at the matter. Sure, there are some side effects that you should keep in mind, but the chance to get better and without any complications with the use of penicillin is the much bigger picture here and we should never forget that. We hope that through today’s article, you have learned everything that you have wanted to know about penicillin and especially its mechanism of the act. We also hope that from today on you will be able to appreciate the existence of penicillin as we have in the past.