Steven’s Science In Cinema: Osmosis Jones (2001)

osmosis jones

Showing movies in class to replace a lecture has always been a student’s dream, and it never hurts for the teacher to show it if the movie is an educational one. In biology classrooms, in the twenty-first century the go-to movie for biology teachers has been Osmosis Jones (2001), directed by Bobby Farrelly, Peter Farrelly,  and Tom Sito. I even remember watching this film at least three times throughout my whole education. It is a great, reminiscent and iconic movie. For me, this movie will always be closely intertwined with biology. Sadly, some of the biology in this film is inaccurate. However, there are plenty of times when a scientific concept is correctly used subtlety in this film.

The antagonist of this film is named “Thrax” which stems from the pathogen anthrax (Bacillus anthracis). Thrax is a pathogen that invades Frank, a medically ignorant human that acts as the setting for most of the movie as it takes place in his body.  The identity of the pathogen that Thrax is, was never identified. The two best theories are anthrax or scarlet fever, but both of these illnesses are bacterial and Thrax was identified to be a virus. The protagonist in this film is Osmosis Jones who is a white blood cell in Frank’s body and can be assumed to be a neutrophil. This is because neutrophils can circulate throughout most of the body and eliminate any foreign microbes at the site of infection, which is Osmosis Jones’ job throughout the film.

Now that both sides have been identified, most of the accuracies and inaccuracies revolve around these two characters, so I will break down this blog into a Thrax section and an Osmosis Jones section.


I'm contagious
  • It is really cool to see how Thrax enters the body because this is a thing that several people look over in their daily life. Every pathogen has to enter your body at some point, and they can do it easily if you invite them all in with your mouth by eating things off the ground or from an animal’s mouth. This initial introduction of Thrax is great because your saliva contains antibodies and white blood cells that combat pathogens. Those that slip through, like Thrax, are the ones that can cause illness.
  • In the same scene, he says “Careful, I’m Contagious”, but he then only shows his virulence in this film. Virulence refers to how much damage a pathogen can do, and contagion (noun of contagious) refers to the transmission of a disease. In fact, Thrax is not good at acting as a contagious pathogen since Thrax does not transmit to another human throughout the entire film.
  • Thrax makes it his goal to kill Frank with a fever, and the way he is going to achieve this is by going to the hypothalamus and turning up the temperature. The hypothalamus is the region where the temperature is controlled, but it is not controlled by pathogens. When a fever occurs, it is in response to a pathogen. Thrax would not have turned up the temperature, the body would have turned up the temperature in response to him.
  • In addition to Thrax’s goal to kill Frank by turning up Frank’s body temperature, he also has the plan to recruit other pathogens to aid in his overall goal. A pathogen would not directly recruit other pathogens, but there are opportunistic pathogens that can present themselves during or after an illness. The flaw with this scene is that Thrax is still alone. In reality, he would have replicated several times. A single “Thrax” cannot cause this much damage. The pathogen would have to replicate several times and be at a higher population size in order to cause any serious illness.

Osmosis Jones:

Osmosis Jones 2
  • The physical appearance of Osmosis Jones is absolutely amazing! You can clearly see his white/grey outer membrane and blue interior, which is most likely his nucleus. This is a cool cartoon personification of a neutrophil! That being said, the ”Saccous-membranous” that Osmosis Jones describes as his white exterior has no scientific merit to it. There is no such thing as a Saccous-membranous.
  • His name…is also completely wrong. While Osmosis Jones is chasing down germs, he morphs and bends to slip through a crack in a wall, which would be a neutrophil slipping through vessel walls or tissues. This would be cellular migration. The term in his name “Osmosis” only refers to the movement of water across a semi-permeable membrane. Osmosis Jones is not water… therefore, he does not perform osmosis.
  • Since Drix is Osmosis Jones’ partner, I decided to put him in this section. Drix’s whole task as symptom relief was portrayed accurately as he mainly focused on the symptoms. Things become inaccurate when he attempts to attack pathogens. A simple cold pill would only relieve symptoms and not attack any pathogens causing the cold. Drix would not have any capability to do so.
  • When Osmosis Jones is attempting to identify Thrax, he is connected to a phone call to the brain which gives him the information that the pathogen is the “red death”. This would not occur in the brain. This identification does occur in the immune system and would be stored in memory T cells and memory B cells. In this case, assuming this is the first exposure Frank has had to the type of pathogen that Thrax is, Osmosis Jones would actually have to contact memory B cells.
  • The “inside man” or virus that is actually on the cop’s side, called an informant, in this film is identified to have originated from a flu vaccine. This is a truly wonderful addition to this film since a vaccine’s job is to prime, or inform your memory B cells and memory T cells on how to fight the illness that it is being vaccinated against. This movie even shows that the flu vaccine would not be able to help fight other illnesses since it only knows about the flu! Beautiful!

The damage that Osmosis Jones causes throughout the movie, much like Thrax, could not have occurred by himself. Whether it is damaging a nerve and causing a whole leg to spasm. Both sides, Osmosis Jones and Thrax, caused a lot of damage to the body. Some of the damage was even caused by the mayor. In reality, most of the damage and symptoms are caused by the immune system in its response.

Osmosis Jones contains a mix of accurate science moments and completely misrepresented concepts that may lead to some misunderstandings in the student community. In light of these misrepresentations, many teachers have shifted this film from learning biological concepts as it is portrayed to learning biological concepts by pointing out how it is misrepresented. There were several other subtle fun and accurate puns throughout the film, but most of the major concepts in the film are misrepresented.


In light of the COVID-19, everyone seems to be interested in movies such as Contagion (2011), directed by Steven Soderbergh, and Outbreak (1995), directed by Wolfgang Petersen. Due to the resurgence of these films, I think it would be a great option to do a review of those two movies. My next blog will mix the two movies which will focus on their portrayal of their approach to the outbreak/pandemic scenario.

– Steven Zeko, Film blogger


Steven’s Bio:

Steven Zeko
Steven Zeko

Steven Zeko is a senior at Lewis University, working towards a Bachelor of Science in Biology and a Bachelor of Arts in Secondary Education. Currently, he is involved in immunology research and Chem-ED research. Following his education, Steven wants to teach Biology, Chemistry, and Physics at a high school level. In his free time, Steven enjoys playing video games, reading, playing golf, and watching movies. He is typically reading two books at any given time, with one book being a science book and the other being any good book that he can find. Currently, Steven is reading Astrophysics for People in a Hurry by Neil deGrasse Tyson and Educated by Tara Westover. His fascination with science began when he was a kid by watching the works of Bill Nye and Neil deGrasse Tyson. Both being wonderful STEM educators, he hopes to invoke their ability to energize a crowd just by educating people about science.


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