The loss of someone close to us is one of life’s most difficult and painful experiences. It affects us deeply—not only emotionally, but also mentally and even physically. Healing from such a loss is rarely simple or quick; grief can last for months, years, or even a lifetime. During this time, many people search for meaning, try to understand the nature of death, or seek ways to cope with the overwhelming sadness and emptiness it brings. This universal human experience has long captured the attention of scientists, who are increasingly exploring not just the psychological impact of grief, but also how our bodies and senses respond to death.
One especially intriguing area of research focuses on the chemical changes that occur in the body after death. Scientists have discovered that when a living organism dies, it begins to release specific chemical compounds as part of the decomposition process. Among these is putrescine, a substance known for its strong, unpleasant odor often associated with decaying flesh. While unsettling, the identification of putrescine’s role in decomposition has important implications for understanding how both humans and animals detect and respond to environmental cues signaling danger or death.
Putrescine, along with similar compounds, acts as a powerful natural warning signal. Animals have evolved to instinctively detect these odors, using them to avoid threats or identify unsafe environments. Recent studies suggest that humans, too, are sensitive to these chemical cues—often without conscious awareness. Psychologists Arnaud Wisman and Ilan Shrira conducted controlled experiments exposing participants to low concentrations of putrescine. Their findings revealed that people became more alert, vigilant, and cautious after exposure. Many participants even moved physically away from the source, displaying clear avoidance behaviors.
What’s particularly compelling is that most participants didn’t consciously recognize the smell or its association with death. Yet, their bodies responded automatically—triggering a primal fight-or-flight response. This indicates that our sensory systems are hardwired to detect chemical signals related to danger, even when we’re not fully aware of them. It highlights a profound connection between our sense of smell and our survival instincts—one that often operates beneath the level of conscious thought.