By Daandii Ragabaa

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OROMIA, Ethiopia — At the banks of rivers and lakes across Oromia, millions gather each year for Irreechaa, the annual Oromo thanksgiving festival. They carry fresh green grass and yellow daisies, dip them into the water, and sing ancient songs of gratitude that have echoed across these lands for thousands of years.

To the Oromo people, Irreechaa is a sacred spiritual and cultural celebration — a time to thank Waaqa (God) for the rains, the harvest, and the gift of life itself. But a growing body of scientific research reveals that this ancient festival is also something else: a sophisticated, multisensory pathway to mental well-being that modern science is only beginning to fully understand.

A Festival Older Than Empires

According to Oromo tradition, Irreechaa was established by Oromo forefathers during the time of Gadaa Melbaa, marking the end of the rainy season known as Ganna. The festival has been celebrated for thousands of years, predating the institutionalized religions of Christianity and Islam. It is rooted in Waaqeffannaa, the traditional Oromo belief in one supernatural power called Waaqa.

Irreechaa was systematically outlawed for more than a century following the fall of the Oromo nation under the rule of Menelik II and subsequent regimes. Despite these challenges, the tradition survived in the hearts of the people and has undergone a powerful revival in recent decades.

As one Oromo historian noted, “Irreechaa has revived putting the Oromo identity foremost before anything else.”

The Sacred Elements

Every element of Irreechaa carries layered meaning. Water holds profound significance — the festival is celebrated at Malkaa (riverside) and Hora (lakeside), where communities gather to dip fresh green grass and flowers into the water. This act symbolizes purification, renewal, and the washing away of the past year’s hardships.

The fresh green grass and yellow daisies carried by participants are symbols of hope (abdi) and renewal. In the Oromo worldview, these plants represent the life and fertility that Waaqa has granted. By carrying them to the water’s edge and offering them, participants express gratitude for the past and pray for future abundance.

The procession to the water is led by the Abbaa Malkaa (lineal chiefs) and Abbaa Gadaa (Gadaa leaders), accompanied by traditional songs, dances, and ululations. Women play a particularly prominent role, walking in front of the leaders. If they stop on the road, the entire procession stops — nobody passes before them, because Oromo culture symbolizes women as sacred and as peace. This is rooted in the Siinqee institution, the customary women’s institution that serves as a peace mission and mediator.

After reaching the water, the Abbaa Malkaa, Abbaa Gadaa, and Qaalluu (spiritual leaders) bless the participants and make speeches on rules and regulations. This blessing carries the authority of the Gadaa system, which regulates political, economic, social, and religious life. Irreechaa is also an occasion when those in conflict bury the hatchet — a powerful, community-enforced deadline for resolving disputes.

What Science Says About Chanting

Chanting, a central practice in Irreechaa’s riverside ceremonies, has been shown to produce measurable reductions in stress and anxiety. A randomized controlled trial conducted in Australia found that just twelve minutes of group chanting — whether vocal or silent — resulted in significant decreases in cortisol levels and self-reported anxiety.

The reduction in cortisol, the body’s primary stress hormone, was similar for both vocal and silent chanting. However, self-reported anxiety decreased more following vocal chanting, suggesting that the act of voicing — singing the songs of Irreechaa — amplifies the psychological benefit.

The study also found that altruism scores increased following both vocal and silent chanting, indicating that the ritual practice fosters pro-social tendencies. Group synchronisation, a feature of communal chanting, is thought to promote cooperation and feelings of connection to others.

Research on singing in groups confirms that music can “reach our deepest emotions without using language or images” and that when people sing together, they share “a form of emotion that carries along the participants so that they experience their bodies responding emotionally in very similar ways.”

This aligns with the experience of Irreechaa participants, who sing together in a shared expression of gratitude and hope. The Marewoo songs sung during the procession express gratitude and hope for the new year. Women sing “Maariyoo… Maareyoo…” meaning “your mercy on us,” while men chant the Irreechaa song with them.

One traditional prayer begins:

“Dukkana gannaa nubaaftee / Booqa Birraa nugarsiiftee / Akkanumatti fuuldura keenyaafis / Waan horre walin nagaa nu godhi”

This translates to: “You have ended the darkness of winter / You have brought us the hope of spring / Likewise, for our future / Make us peaceful with what we have gathered.”

The song is both thanksgiving for the past and prayer for the future — a complete expression of the Oromo relationship with Waaqa.

The Healing Touch of Grass

The fresh green grass carried by Irreechaa participants — dipped into the water as an offering and symbol of renewal — also carries documented psychological benefits when touched. A 2024 study published in the Journal of Urban Health investigated the effects of tactile interaction with real grass versus artificial grass among older adults.

The findings showed that touching real grass produced a heightened sense of relaxation and calmness, increased mean systolic blood pressure reduction, and upward trends in brainwave patterns associated with relaxation.

A separate study involving young adults found that five minutes of tactile stimulation with real landscape grass, applied through the palm of the hand, produced significant reductions in diastolic blood pressure, increased alpha brainwave activity (a marker of relaxed alertness), and alleviation of anxiety compared to a control condition.

The researchers concluded that “palming grass — the act of touching grass with one’s hand — has a calming effect on both physiological and psychological responses to stress.”

For Irreechaa participants, the act of holding grass and dipping it into the water is thus not only a spiritual gesture but a tactile experience with measurable calming effects on the nervous system.

The Restorative Power of Water

Irreechaa’s setting at rivers and lakes — Irreechaa Malkaa — places participants in what researchers call “blue spaces,” environments featuring water. A systematic evidence map of blue space research confirms that contact with water environments is associated with mental health benefits, including reduced stress and enhanced well-being.

A landmark 19-country study involving over 17,000 participants found that all blue space settings were recalled as restorative, with rural rivers and canals among the most restorative. The study also found a reciprocal relationship between restoration and nature connectedness — the more restored an individual felt, the more connected to nature they became, and vice versa.

Research specifically examining Irreechaa notes that water’s acoustic properties and its natural setting “engage biophilia, enhancing mental well-being.” Acoustically, water’s ability to transmit sound four times faster than air creates immersive soundscapes, amplifying the emotional impact of riverside songs.

The Oromo people have long understood what environmental psychology now confirms: that gathering at the water’s edge, with the sound of flowing water and the sight of its expanse, creates a sense of calm and repose that supports spiritual reflection and communal bonding.

The Synergy of Sound, Grass, and Water

What makes Irreechaa psychologically powerful is not any single element in isolation, but their combination. The ritual brings together vocal chanting, tactile contact with fresh grass, and immersion in a water environment — a multisensory experience that engages multiple pathways to well-being simultaneously.

Research on Irreechaa explicitly describes this synergy: “water’s fluidity and reflectivity, paired with the resonance of sound, create multisensory rituals that deepen spiritual engagement.”

The study notes that “psychologically, chanting and singing reduce stress and trigger dopamine release, fostering emotional uplift and communal bonding,” while “natural water settings engage biophilia, enhancing mental well-being and aligning with the spiritual clarity sought in rituals.”

The communal dimension is equally important. The Oromo people gather at sacred rivers and lakes to thank their creators for the greenery that the rains have brought. Men, women, the elderly and the young all join in, adorned in eye-catching clothes and jewellery. They sing, dance, share stories and place freshly cut grass and flowers in water — a symbol of life, renewal and hope.

For a community gathering after the isolating rainy season, this reconnection — through shared sound, shared touch of grass, and shared presence at the water — serves as a collective psychological renewal. The festival’s requirement for reconciliation before participation further reinforces this, creating a culturally mandated pathway for repairing broken social bonds before they solidify into chronic distress.

A Culturally Rooted Pathway to Well-Being

For the Oromo people, Irreechaa is a spiritual and cultural celebration. The scientific evidence now confirms what generations have experienced intuitively: the ritual’s elements — sound, grass, and water — are also powerful tools for mental health.

In a context where formal mental health services are scarce, Irreechaa offers an accessible, culturally meaningful pathway to stress relief, emotional restoration, and social connection.

The psychological power of Irreechaa lies in its integration of body, mind, and community — a holistic approach to well-being that modern research is only beginning to fully understand.

As the festival continues to grow in participation and recognition, these ancient symbols remain as relevant as ever — reminding the Oromo people of their connection to Waaqa, to the earth, and to one another.

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Irreechaa is celebrated annually at the banks of rivers and lakes across Oromia, with Irreechaa Malkaa taking place in mid-September at the end of the rainy season, and Irreechaa Tulluu during the dry season at the beginning of spring.