Do Animals Self Medicate with Plants?


Apparently some do. If you have seen a dog eating grass prior to vomiting then you may have witnessed animal self-medication of a sort. The jury is still out on whether this is a conscious use of an emetic or not. Would the dogs have vomited eventually anyway? This is a question sometimes raised and in response it could be said that people would probably recover from a headache eventually, but we tend to reach for the medicine cabinet to move things along a bit.

Some other examples are less equivocal. Primatologist, Dr. M.A. Huffman of Kyoto University noted that when one of his Chimpanzee study subjects in Tanzania was looking ill and lethargic he witnessed her seek out and eat the pith of the Bitter leaf tree (Vernonia amygdalina). When Huffman’s assistant Mohemadi Seifu Kalunde informed him that the local Tongwe tribe used various other parts of the tree to treat Stomach Cramps, Malaria Fever and Intestinal Parasites, Huffman noted the connection and then established a new medical use for a part of the plant hitherto unrecognized in the 40 years that the plant has been known to medical science. In the abstract of his paper “Animal self-medication and ethno-medicine: exploration and exploitation of the medicinal properties of plants” Dr. Huffman writes

“Early in the co-evolution of plant-animal relationships, some arthropod species began to utilize the chemical defenses of plants to protect themselves from their own predators and parasites. It is likely, therefore, that the origins of herbal medicine have their roots deep within the animal kingdom… Both folklore and living examples provide accounts of how medicinal plants were obtained by observing the behaviour of animals. Animals too learn about the details of self-medication by watching each other.”

That’s pretty unequivocal.

My search of the NCBI PubMed database for animal self medication yielded 295 published medical papers, evidence of a growing branch of human science, Phytopharmacognosy, dedicated to the acquisition of pharmacological knowledge from the animal kingdom. So the answer seems to be that some animals do self medicate with plants, and that science can learn from them.
Some animals also self-medicate to counter undesired phytopharmaceutical influences. After eating toxic plant matter African elephants and Brazilian parrots eat mineral rich clays to detoxify their vegetarian diets.

Recently, via a program on Community TV channel I heard of a translocated black rhino in Namibia that died from ingested plant toxins and I now wonder whether it ate unfamiliar plants or whether its new habitat lacked the specific minerals that could have countered the toxicity? It may be necessary to move their medications together with these animals for successful translocation.



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