Consider for a moment how lucky we are in the modern era. Sure, many of us experience the stress of deadlines, bills, and overstimulation. But we often take for granted how humans have transcended the throes of tooth and claw that our ancestors endured. Nature is a cycle of life and death; an ongoing war between countless species. One of our oldest enemies—bacteria—could have ended us in the past, but we’re now lucky enough to have access to pills that kill it off.

Antibiotics save over 200,000 lives each year in the United States alone. But humans aren’t the only species with a tendency to adapt and overcome; species of bacteria are mutating and developing resistance. Now, researchers are eyeing up new sources of antibiotics to counter this threat—some have placed cannabis in the crosshairs.

The Importance of Antibiotics

Antibiotics are an essential weapon in the age-old war against microbial life. Of course, not all microscopic organisms inflict disease; the human gut contains trillions of bacteria, fungi, and viruses that help us to digest food and bolster our immune system. But many other species of microbes don’t work in such a symbiotic manner with the human body.

There are myriad species and strains of infectious bacteria. These organisms can work their way into the human body through various means, including contact, airborne, and droplet transmission. For example, eating a poorly cooked piece of food often serves as the entryway for some species.

However, infections can occur at any site in the body. The symptoms either arise from the bacteria itself, or the body's reaction to its presence. Bacteria vary in their pathogenicity (their potential to cause disease); only a small percentage of species cause infection and disease in humans, but many of these can cause serious damage.

Every organ in the human body is susceptible to bacterial infection. Species that attack the meninges (membranes that protect the brain and spinal cord) can cause meningitis. Those that go after the lungs can cause pneumonia. Staphylococcus aureus, which usually occupies the skin, can gain entrance to the body via wounds and infect the heart valves and abdomen.

A Brief History of Antibiotics

Thankfully, antibiotics have helped to render previously deadly infections into minor inconveniences. Infectious diseases topped the list as the leading cause of mortality for most of human existence. The rise of antibiotics has given us an effective weapon against this invisible enemy.

Evidence suggests that humans have harnessed the power of antibiotics for millennia. For example, traces of the antibiotic tetracycline are present in human skeletal remains[1] from ancient Sudanese Nubia dating back to 350–550 AD.

However, most of us associate the emergence of live-saving antibiotics with Alexander Fleming and the start of the “antibiotics era”. Fleming discovered the antibiotic penicillin while studying Staphylococcus bacteria. After leaving a Petri dish filled with the bacteria next to an open window, he returned to find the dish contaminated with mould. However, the new fungal arrival had also successfully killed off the infectious bacteria.

This ground-breaking discovery took place on September 3rd, 1928, and went on to save an estimated 200 million lives[2].

A Brief History of Antibiotics

How Antibiotics Work

Antibiotics work in two primary ways. They either help to slow cells down (bacteriostatic) or kill them (bactericidal). Bacteriostatic antibiotics stall bacterial cellular activity but don’t cause them to die outright. They essentially put a pause on their ability to multiply, which gives the immune system ample opportunity to wipe out the current infection. These drugs achieve this by interfering with DNA replication, metabolism, and protein production.

In contrast, bactericidal antibiotics directly kill bacteria. They do so by preventing bacteria from forming a cell wall, which quickly leads to their demise. Penicillin antibiotics are bactericidal, including penicillin V for sore throats, and amoxicillin for chest infections.

Antibiotics also differ in the species of bacteria that they target. Some are classed as “broad spectrum” and attack numerous species, including beneficial bacteria that reside in the gut. This can lead to an imbalance within the microbiome and possible digestive issues. In opposition to this mechanism, “narrow-spectrum” antibiotics are more selective in the species they inflict damage against. They only affect between 1–2 types of bacteria, leaving many of our native microbes to live their lives in peace.

  • Gram-Positive vs Gram-Negative Bacteria

Some bacteria are more resistant to antibiotics and the antibodies created by our immune system than others. Bacteria fall into one of two categories: gram-positive and gram-negative. This name derives from a staining test used to identify species of bacteria.

These two types differ based on their cell walls. Gram-positive bacteria have no outer membrane, a complex cell wall, and a thick peptidoglycan (protein and carbohydrate) layer. Gram-negative bacteria, on the other hand, feature an outer lipid membrane and a thin peptidoglycan layer. As gram-negative species have a thicker outer layer, they're often more impervious to antibiotics.

Although the term “antibiotics” literally means “against life”, these drugs only work on a select category of microbes, namely bacteria. Antibiotics cannot protect the body against viruses, for several reasons. First of all, viruses enter host cells to replicate, and bacteriostatic antibiotics do not attack host cells. Second, viruses don’t possess cell walls, which means bactericidal antibiotics have nothing to attack.

What Is Antibiotic Resistance?

Antibiotics have saved millions of lives, and continue to do so. But bacteria refuse to wait in position like sitting ducks. Like all other life forms on Earth, they possess the ability to adapt to threats, overcome challenges, and ensure their own survival. This trait has enabled some species to develop resistance to antibiotics. The source of this trouble lies in something that guides the development of all life: natural selection.

Just like other organisms, individual bacteria develop random mutations. Some of these are functional, whereas others are completely useless. However, every now and then, one mutation comes along that improves an organism's ability to adapt and survive. Some bacteria develop mutations that make them more resistant to antibiotics than others. As those that are susceptible to antibiotics die off, those that possess the beneficial mutation gain more resources and multiply.

Examples of these successful mutations include the development of Staphylococcus aureus into MRSA (methicillin-resistant Staphylococcus aureus). This form of bacteria has developed resistance to methicillin and penicillin, and manages to keep constructing its cell wall in the face of these antibiotics thanks to a genetic tweak.

The Looming Threat of Antibiotic Resistance

The World Health Organization (WHO) views antibiotic resistance as one of the biggest threats to global health and development. Although antibiotic resistance develops naturally, the WHO points toward the misuse of antibiotics in humans and animals as a factor that aids the process. As a result, infections such as pneumonia, tuberculosis, gonorrhoea, and salmonellosis are becoming harder to treat.

Individuals can help to curb this phenomenon by only taking antibiotics prescribed by health professionals, and by never taking them when they don’t need to. Health professionals can also help to slow the rate of antibiotic resistance by refusing to overprescribe these medicines.

Researchers are also playing their part by hunting down new forms of antibiotics that can tackle mutated strains. But where are they looking? Some are eyeing up cannabis as a potential source of novel antibiotics.

The Looming Threat of Antibiotic Resistance

Is Marijuana a Potential Antibiotic?

How can a natural plant possibly stop mutating bacteria in its tracks? Well, first, antibiotics are derived from fungi—a group of naturally occurring organisms. Second, plants have engaged bacteria and other microbes in an evolutionary arms race over millions of years. They have become rather efficient in producing molecules that keep these pathogens at bay.

More specifically, plants largely protect themselves by manufacturing secondary metabolites. These molecules aren’t involved in the growth or development of a plant, but rather serve as chemical weapons. Cannabis plants have quite the arsenal, producing over 100 cannabinoids and 200 terpenes for this purpose.

Antibiotic Potential of Cannabinoids and Terpenes

You’ve probably heard of THC and CBD. Both of these famous chemicals belong to the cannabinoid class. This family of substances also occurs in several other plant species, and interfaces with the endocannabinoid system in humans—a body-wide network that helps to regulate many other physiological systems.

Researchers have explored the antibacterial properties of cannabis extracts and cannabinoids for several decades. The first studies took place in the 1950s. Although the researchers observed bactericidal effects, a lack of knowledge on cannabis phytochemistry at the time prevented them from determining the active constituents.

However, researchers made a breakthrough in 1976 when they discovered the bacteriostatic and bactericidal actions of THC and CBD against gram-positive bacteria. Studies have also tested hemp essential oils against some forms of bacteria.

These preparations include novel cannabinoids, and terpenes such as pinene, limonene, and ocimene. Studies found moderate to good antimicrobial activity in vitro, suggesting that a combination of cannabis constituents might prove beneficial in future human research.

Studies have focused on several different cannabinoids in the search for novel antibiotics. THC, the main psychotropic component of cannabis that causes the “high”, appears to show some promise. Studies are finally exploring its efficacy in greater depth, and findings from a 2008 paper justify further exploration into its effects[3] against MRSA.

What About Other Antibacterial Cannabinoids?

THC often occupies the limelight when it comes to cannabis research. Of course, its psychotropic status is always a hot topic of debate. While some users appreciate these effects, non-psychotropic cannabinoids are more attractive to researchers as they don’t expose patients to such side effects.


CBD, or cannabidiol, produces no high. Instead, users report a clear-headed effect that doesn’t impair cognitive function. CBD has become the focus of hundreds of studies exploring its possible benefits, including its action against antibiotic-resistant bacteria.

A 2021 paper titled “The antimicrobial potential of cannabidiol” marked some serious progress[4] in this domain. The data documents CBD’s potential to combat gram-negative “urgent threat” bacteria such as Neisseria gonorrhoeae.

Have you ever heard of cannabigerol, aka CBG? Its acidic form, CBGA, is known as the “mother cannabinoid”. This non-psychotropic molecule serves as the chemical precursor to other cannabinoids, including THC and CBD. Researchers have also investigated CBG for its antibiotic potential, with studies comparing it against vancomycin—a medication used to treat numerous types of bacterial infections—in mouse models of MRSA.

The Future for Cannabis as an Antibiotic

New forms of antibiotics are urgently needed. While the medical profession continues to change the way it prescribes these medicines, researchers are scrambling to find new sources of antibiotics to tackle mutated strains. Might cannabis serve as a reservoir of these compounds? We’ll have to wait and see as studies continue to discover the practical application of cannabinoids in the human plight.

External Resources:
  1. A Brief History of the Antibiotic Era: Lessons Learned and Challenges for the Future
  2. One discovery that changed the world | Florey 120 Anniversary | University of Adelaide
  3. Antibacterial cannabinoids from Cannabis sativa: a structure-activity study - PubMed
  4. The antimicrobial potential of cannabidiol | Communications Biology
This content is for educational purposes only. The information provided is derived from research gathered from external sources.

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