Surreal illustration of a litchi fruit with glowing particles.

Litchi Fruit and Brain Health: Unraveling the Mystery of Childhood Illness in India

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Reese Marlowe in Health & Wellness December 2025 • 4 min read.

"New research sheds light on the real culprit behind a recurring brain illness in children, clearing pesticides and pointing to a natural compound in litchi fruit."


Every year, as the litchi fruit ripens in the orchards of Muzzaffarpur, India, a frightening outbreak occurs. Children, otherwise healthy, are suddenly struck by a severe brain illness, leading to high fatality rates and leaving families in despair. This annual epidemic, known as Acute Encephalitis Syndrome (AES), has baffled doctors and scientists for years, becoming a major public health concern in the region.

Initially, suspicion fell on viral infections, but repeated investigations failed to identify any common viral agent. The search for answers led researchers down various paths, including the possibility of pesticide exposure. The litchi harvest season coincides with the outbreak, raising concerns about the potential link between agricultural practices and the children's illness.

However, a new study is turning the tide on these long-held beliefs. This research points away from pesticides and instead shines a spotlight on a naturally occurring compound found within the litchi fruit itself. The findings offer a fresh perspective on the cause of AES and pave the way for more targeted prevention and treatment strategies.

MCPG: The Real Culprit Behind the Outbreaks?

Surreal illustration of a litchi fruit with glowing particles.

The groundbreaking study, published in Toxicology Letters, focuses on methylenecyclopropyl glycine (MCPG), a compound found in litchi fruit. Researchers Somya Asthana, Sumita Dixit, Anshuman Srivastava, and their team meticulously investigated the presence of pesticide residues and MCPG in litchi fruits from the Muzzaffarpur region.

Their research involved a comprehensive analysis of litchi samples, employing sophisticated techniques like gas chromatography and liquid chromatography-mass spectrometry (LC-MS/MS). This allowed them to accurately measure the levels of various pesticides and MCPG in different parts of the fruit, including the outer covering and the edible pulp.

The key findings of the study can be summarized as follows:
  • Pesticide Residues: The outer covering of the litchi fruit showed traces of common pesticides like malathion and DDT. However, the edible pulp, the part children consume, had no detectable pesticide residues.
  • MCPG Detection: MCPG was found in both ripe and semi-ripe litchi pulp. Notably, the concentration of MCPG was higher in semi-ripe fruits.
  • Animal Studies: To confirm the role of MCPG, the researchers conducted experiments on young rats. They found that the animals, when starved and given doses of litchi seed powder (containing MCPG), experienced a drop in blood sugar levels (hypoglycemia).
These results suggest that MCPG, particularly when consumed on an empty stomach, may be the primary cause of AES in Muzzaffarpur. The compound's ability to induce hypoglycemia, especially in undernourished children, aligns with the observed symptoms of the illness.

What This Means for Prevention and Future Research

The discovery of MCPG as a key factor in AES opens new avenues for prevention and treatment. Public health initiatives can now focus on educating communities about the risks of consuming litchi fruit, especially unripe ones, on an empty stomach. Ensuring that children have access to regular meals, particularly during litchi season, can help prevent hypoglycemia. Further research is needed to fully understand the mechanisms by which MCPG induces hypoglycemia and to develop targeted interventions to mitigate its effects. These insights offer hope for safeguarding the health and well-being of children in litchi-growing regions and preventing future outbreaks of this devastating illness.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

Everything You Need To Know

1

What is Acute Encephalitis Syndrome (AES), and why is it a major health concern?

Acute Encephalitis Syndrome (AES) is a severe brain illness that affects children in the Muzzaffarpur region of India during the litchi season. It is characterized by high fatality rates, causing significant distress to families. The mysterious nature of the illness, coupled with its recurring outbreaks, has made AES a major public health concern, prompting extensive research to identify its cause and develop effective prevention and treatment strategies.

2

What role did pesticides initially play in the investigation of the brain illness affecting children?

Initially, suspicion fell on various factors, including viral infections and pesticide exposure, due to the coincidence of the illness with the litchi harvest season. Researchers investigated the potential link between agricultural practices and the children's illness. However, studies revealed that the edible pulp of the litchi fruit, which children consume, did not have detectable pesticide residues, shifting the focus to other potential causes.

3

What is MCPG, and how was it linked to the brain illness affecting children?

MCPG, or methylenecyclopropyl glycine, is a naturally occurring compound found in litchi fruit. Research, published in *Toxicology Letters*, identified MCPG as a key factor in Acute Encephalitis Syndrome (AES). The study found MCPG in the litchi fruit pulp, with higher concentrations in semi-ripe fruits. Experiments on young rats showed that MCPG, when consumed on an empty stomach, led to a drop in blood sugar levels (hypoglycemia), which aligns with the symptoms observed in children affected by AES.

4

How was the presence of MCPG and pesticides determined in litchi fruits?

The research team used advanced techniques like gas chromatography and liquid chromatography-mass spectrometry (LC-MS/MS) to analyze litchi samples. These methods allowed them to accurately measure the levels of various pesticides and MCPG in different parts of the fruit, including the outer covering and the edible pulp. This comprehensive analysis revealed the presence of pesticides in the outer covering but not the pulp, while MCPG was detected in the pulp, particularly in the semi-ripe fruit.

5

What are the implications of the discovery of MCPG for preventing and treating the brain illness?

The identification of MCPG as a key factor in Acute Encephalitis Syndrome (AES) opens new avenues for prevention and treatment. Public health initiatives can now focus on educating communities about the risks of consuming litchi fruit, especially unripe ones, on an empty stomach. Ensuring that children have access to regular meals, particularly during litchi season, can help prevent hypoglycemia, which is linked to the illness. Further research is needed to fully understand the mechanisms by which MCPG induces hypoglycemia and to develop targeted interventions to mitigate its effects, offering hope for safeguarding the health and well-being of children in litchi-growing regions.

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