Frogs in Medicine

Photo sourced from: Xenopus Laevis Research – University of Rochester Medical Center

by Kerry Calkins

Frogs in Medicine: From Ancient Symbols and Remedies to Modern Breakthroughs

For over 5,000 years, frogs have transformed medicine. From their symbolic role in ancient mythologies to their place at the forefront of biomedical research, these amphibians have served as invaluable tools in the quest to understand the human body. Whether applied to wounds as a remedy or powering advances in science, frogs have consistently leapt ahead in their scientific significance.

Frogs at the Frontier: From Pregnancy Tests to Regeneration

Photo sourced from: Xenopus Laevis Resource – University of Rochester Medical Center

No amphibian has influenced biological sciences more than Xenopus laevis, the African clawed frog.

Once known for its use in early pregnancy tests, Xenopus rose to fame when John Gurdon performed the first successful nuclear transplantation in 1958, an experiment that later earned a Nobel Prize and laid the groundwork for stem cell therapy (22).

Today, Xenopus is pivotal in immunology and genetics. At the University of Rochester, Dr. Jacques Robertleads a world-renowned Xenopus research center offering transgenic lines, monoclonal antibodies, and tools for CRISPR-based gene editing (17, 18). Thanks to the work of scientists, Xenopus boasts a fully sequenced genome and was found to have immune features like MHC-restricted T-cells and class-switching B-cells, making it a powerful model for studying cancer, infections, and autoimmune diseases (10, 17, 18).

Beyond genetics and immunology, frogs are central to research in regeneration, pain management, and endocrinology. Certain frog species (including Polypedates tadpoles and Xenopus laevis froglets) can regenerate amputated limbs by forming a blastema, a mass of undifferentiated cells that rebuilds tissues, offering valuable insights for human regenerative medicine (7).

Frog neuromuscular junctions are widely used to study disorders like ALS (Amyotrophic Lateral Sclerosis) and myasthenia gravis, shedding light on how nerves communicate with muscles (11). Meanwhile, frog skin secretions have inspired new pain-resistant drugs and antimicrobial treatments, thanks to their natural defense compounds (21).

Much of our foundational understanding of thyroid hormone’s role in growth and development stems from early 20th-century experiments on frogs. Researchers discovered that triiodothyronine (T3) is essential for metamorphosis; removing the thyroid gland from tadpoles prevented this transition, while premature exposure to thyroid tissue induced early metamorphosis, resulting in undersized adult frogs (15).

Cultural Origins and Ancient Medical Uses

Frogs first entered medical imagination through spirituality and traditional healing.

Photos sourced from: Heqet | History, Egyptian Goddess,  Heqet

In Ancient Egypt, the frog-headed goddess Heqet symbolized fertility and rebirth (1, 2, 8, 13).

    • In English, Heqet’s name is sometimes spelled as Hequetat, Hekat, or Heket (1, 2, 8, 13).

Dried frogs photo: Readily found on Chinese medicine wholesale sites

Chansu infographic: The origin, components, functions, toxicity, and mechanisms of Chansu

In China, as early as 200 BCE, physicians used wa pi – dried frog skin from Rana amurensis – to treat infections and swelling (20). Compounds from frog venom (Chansu) were also applied to the skin for cardiovascular ailments due to their digitalis-like effects on cardiac contraction (4, 5, 6).

Photo sourced from: Greek Intellectual Life under the Roman Empire

In Ancient Greece, Dioskourídēs recommended frog-based poultices for their purifying properties (19).

    • Poultices refer to a soft moist mass of material applied to the body to relieve soreness and inflammation, often kept in place with a cloth.
    • Pedánios Dioskourídēs (Πεδάνιος Διοσκουρίδης, c. 40–90 AD) was a Greek physician, pharmacologist, botanist, and author of De materia medica (On Medical Material), a 5-volume Greek encyclopedic pharmacopeia on herbal medicine and related medicinal substances, that was widely read for more than 1,500 years (19, 12).

Tribal Photos: A look at the oldest surviving tribes of Northeast India

Picture of Rana aurora by Walter Siegmund: Wiki Commons

In India, tribal communities from the Western Ghats, Nagaland, and Arunachal crush the flesh of Rana spp. into a paste and apply it to wounds for healing (16, 24, 26, 27).

These early practices reflect a shared cross-cultural recognition, both symbolic and practical, of the frog’s unique biology and transformative nature: a creature capable of regeneration, living in two worlds, and serving as a living metaphor for healing.

Dissection and Discovery: Frogs in Classical Science

Dissected Frog Wall Mount

Photo sourced from: Andreas Vesalius | De humani corporis fabrica | The Metropolitan Museum of Art

The Renaissance and Enlightenment marked frogs’ transition from mythology to modern science.

  • Andreas Vesalius, in his anatomical text De Humani Corporis Fabrica (1543), dissected frogs to demonstrate comparative organ systems and challenge Galenic dogma. But perhaps the most iconic leap came in 1791, when Luigi Galvani famously demonstrated “animal electricity” by stimulating frog legs with static charge, hence founding electrophysiology and inspiring Alessandro Volta’s battery (9).

Frogs became favored for their accessible neuromuscular systems which are simple to manipulate, yet biologically similar to human physiology.

The Educational Amphibian: Frogs in Medical Training

Building on their classical role, frogs became educational staples in the 20th century, when frogs were indispensable in medical classrooms:

  • In 1950s Sri Lanka, students at the University of Colombo observed real-time nerve and muscle responses in frogs to learn physiology (25).
  • By 1969, Colombo won an animal ethical award for an animal facility to ensure ethical and controlled use of frogs and other species in research, aligning with emerging animal welfare standards (23).

Ethics and Evolution of Practice

Chart sourced from: The 3Rs | NC3Rs

As the role of frogs in science has grown, so too has the scrutiny of their treatment.

  • Institutional protocols now enforce the “3Rs” of animal research: Replacement, Reduction, and Refinement.
  • From refined anesthesia to non-invasive imaging, researchers strive to ensure humane and justified use of these remarkable creatures (3).
    • A 2023 case report detailed successful anesthesia and surgery on a cane toad undergoing femoral repair, illustrating improved standards of care for amphibians and the growing role of veterinary medicine in research ethics (14).

Small Creatures, Giant Leaps

From sacred emblems of rebirth to trailblazers in physiology and biomedical research, frogs have made extraordinary contributions to the advancement of medical science. They’ve illuminated our understanding of electricity, immunity, development, and regeneration. Whether in a petri dish, a genetics lab, or a surgical suite, frogs continue to leap beyond expectations, proving that even the smallest creature can spark some of the greatest scientific breakthroughs.

Photo sourced from: Xenopus Laevis Research – University of Rochester Medical Center

References

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