What Gives A Decaying Body Its Distinctive Odor?

A decaying body emits a distinctly foul, repulsive odor. The odor of a decaying body is so invasive and profound that many people find it difficult to forget. You may wonder what exactly causes a decaying body to have such an intense, nauseating odor.

The Decomposition Process and the Smell of Death

The decomposition process commences at the moment of death. Within a couple of days, a body can begin to give off a foul smell, an odor arising from the progress of the decomposition process.

At the foundation of the decomposition process, and the rise of the distinctive odor associated with a decaying body is bacteria that naturally exist in a living person’s body. The most common types of healthy bacteria found in the body of a human being are:

  • Lactobacilli
  • Bifidobacteria
  • Escherichia coli
  • Streptomyces
  • Rhizobia
  • Cyanobacteria

The highest concentration of bacteria in the human body is in the pancreas and the intestines. For example, some bacteria are involved in the digestion process.

When a person dies, the blood flow around the body comes to an immediate end. When this occurs, bacteria in the body no longer have a ready resource for nutrients. This particularly is the case in the pancreas and intestines.

At this juncture, bacteria “turn” on its host. Bacteria begin to “feed” on the body itself, particularly initially on the pancreas and intestines. Within a couple of days following the death, the work of bacteria on the pancreas and intestines will reach a juncture that these organs are nearly completely broken down. This causes bacteria to be released in large quantities throughout the rest of the body.

As this process progresses, gases are created. Within little time, the body begins to bloat, and the gases are released from the body into the environment surrounding the remains. These gases are what combine to form the foul odor associated with a decaying body.

As the decomposition process continues, the stench grows even stronger and more pervasive. Eventually, as the decomposition process reaches its end, the stench of death begins to fade.

Organic Compounds, Gases, Chemical Compounds and the Stench of Decay

Throughout the decomposition process, an amazing number of chemical compounds come into play, combining to form the foul stench associated with death and decaying remains. In fact, the decomposition process involves over 400 chemical compounds. Of that number, more than 30 are different types of gases.

In addition, the factors that play into the stench of decomposition beyond organic compounds and gases include:

  • The environment surrounding the body
  • Composition of the bacterial population in the body
  • Genetics of the deceased individual (to a lesser degree)
  • Diet of the deceased individual (to a lesser degree)

There are six primary gases that have the most significant impact on the distinctive odor of a decaying body. These are:

  • Cadaverine and putrescine (rotting fish odor)
  • Skatole (feces odor)
  • Indole (mothball-like odor)
  • Hydrogen sulfide (rotten egg odor)
  • Methanethiol (rotting cabbage odor)
  • Dimethyl disulfide and trisulfide (foul garlic odor)

By far the two most common gases that contribute to the putrid smell of a cadaver are putrescine and cadaverine. These two gases initially were isolated by a German doctor in 1885. These gases repel nearly all animals. However, there are certain insects that are attracted by the stench created by these gases. Included on that list are flies, which are drawn to decomposing bodies. Flies lay their eggs on or in decomposing bodies, which transition into maggots.

Technology and the Decomposition Odors

The combination of chemical compounds and gases does change over the arc of the decomposition process. In other words, the stench associated with decay does alter to some degree over time. A layperson is not likely to detect these changes.

Scientists and investigators are capable of identifying these alterations in decomposition odor. They utilize what is known as gas chromatography as a means of identifying the specific gas composition surrounding a corpse. This testing permits a relatively precise determination as to where a body is in the decomposition process, and the timeframe in which a death occurred.

The stench given off by a decomposing body is not only crucial to identifying the time of death but also in finding a body in the first instance. Technology now exists that is referred to as an “electronic nose.” This equipment is able to detect faint amounts of gases like cadaverine and putrescine during a search for a body.