Ecological medicine is a new approach to health science that draws on a very old idea: connecting with each other, with animals and plants, and with the natural world fosters health and well-being for people and the planet.

“Everything you suspected was good for you -- fresh air, trees, animal companions, purpose, reciprocity -- turns out to have peer-reviewed backing,” said Rebecca Calisi Rodríguez, associate professor of neurobiology, physiology and behavior and director of the Green Care Lab at the University of California, Davis.

Ecological medicine also explicitly integrates Indigenous peoples’ understanding of how humans belong to and relate with the natural world.

Calisi Rodríguez, Professor emeritus Lynette Hart of the School of Veterinary Medicine and Associate Professor Alessandro Ossola of the Department of Plant Sciences and Urban Science Lab coauthored a consensus statement defining the field of ecological medicine, which was published Oct. 25 in the journal Ecohealth.

The effort grew out of a 2024 symposium and workshop at UCLA to which Calisi Rodríguez, Hart and Ossola were all separately invited. The event was organized by faculty at the UCLA Department of Psychiatry and Behavioral Sciences, notably Professors Helen Hansen and Michael Makhinson, with Landon Pollack, visiting scholar at Yale University. Hansen and Pollack are now director and codirector, respectively, of the UCLA Ecological Medicine & Psychedelic Studies Initiative.

“The organizers built a community that was very diverse, with very open conversations,” said Ossola.

Hart, who officially retired from UC Davis in 2024 at age 85, has studied and taught about animal behavior and human-animal connections for more than four decades. Much of the research on health benefits of human-animal interaction has focused on direct therapeutic benefits, she said.

“We need to take a wider perspective,” she said. “The goal is a new kind of medicine that fosters health rather than chasing diseases.”

Ecological Medicine expands on the One Health concept. One Health emphasizes how humans, wild and domestic animals and the environment influence health and disease, especially infectious diseases.

Ecological Medicine goes beyond One Health by looking at the psychological and social connections amongst people, animals and the environment and how they can foster health and wellbeing.

Ossola’s Urban Science Lab at UC Davis studies interactions among people, plants and forests, technology and the built environment. For example, the lab measured the amount of shade, including tree canopy, at elementary schools in California and examined the effect on temperatures on school playgrounds.

Urban landscapes should be seen as public health assets just like emergency rooms or pharmacies, Ossola said.

“We know that if you live in a more natural environment with connection to nature, it has escalating effects on health,” he said. For example, the Japanese practice of shinrin-yoku or “forest bathing,” practicing mindful relaxation in a natural setting, has been shown to decrease stress. The British National Health Service’s Green Social Prescribing program supports nature-based activities to improve mental and physical health.

“There’s a reason people put plants in their homes,” Ossola said.

Calisi Rodríguez began her scientific career studying how stress hormones affect the brain and behavior, especially in birds. Since the pandemic, she has established the Green Care Lab near UC Davis to study not only how stress harms us, but how nature can heal.

“After enough years staring at stress hormones, I realized I didn’t want to spend the rest of my career documenting what breaks us. I wanted to study how we heal,” she said. “Ecological Medicine is a growing field I believe in so deeply that I’m reshaping my entire research program around it.”

UC Davis and Ecological Medicine

UC Davis is ideally placed to be a leader in this new field. It is the biggest, greenest campus in the UC system, a recognized leader in sustainability, environmental research and teaching, veterinary and human medicine, and biological sciences; with a culture that fosters breaking out of scientific silos and encouraging public service.

The UC Davis Arboretum serves the whole community, providing a calm, natural environment of plants, birds and aquatic life steps from classrooms and laboratories.

The UC Davis Sheepmowers project, bringing sheep to graze in the central campus, is already surveying mental health impacts for students along with the ecological and operational impacts for the campus.

Dairy cattle by the Tercero dorms, free-ranging turkeys and semi-feral cats are popular campus characters.

This paper marks the birth of a new field, the moment health science stops hovering over the wreckage asking “What went wrong?” and finally turns around to ask, “OK, but what helps us stay upright in the first place?” Calisi Rodríguez said.

“Ecological Medicine tells us how to create lives worth living,” Calisi Rodríguez said. “Giving this field a name gives us a compass, a vocabulary, and a way to study how humans, communities and ecosystems can actually thrive, not just survive.”