Africa Health Check: Probing Cultural Bias in Medical LLMs

Charles Nimo, Shuheng Liu, Irfan Essa, Michael L. Best


Abstract
Large language models (LLMs) are increasingly deployed in global healthcare, yet their outputs often reflect Western-centric training data and omit indigenous medical systems and region-specific treatments. This study investigates cultural bias in instruction-tuned medical LLMs using a curated dataset of African traditional herbal medicine. We evaluate model behavior across two complementary tasks, namely, multiple-choice questions and fill-in-the-blank completions, designed to capture both treatment preferences and responsiveness to cultural context. To quantify outcome preferences and prompt influences, we apply two complementary metrics: Cultural Bias Score (CBS) and Cultural Bias Attribution (CBA). Our results show that while prompt adaptation can reduce inherent bias and enhance cultural alignment, models vary in how responsive they are to contextual guidance. Persistent default to allopathic (Western) treatments in zero-shot scenarios suggests that many biases remain embedded in model training. These findings underscore the need for culturally informed evaluation strategies to guide the development of AI systems that equitably serve diverse global health contexts. By releasing our dataset and providing a dual-metric evaluation approach, we offer practical tools for developing more culturally aware and clinically grounded AI systems for healthcare settings in the Global South.
Anthology ID:
2025.emnlp-main.1639
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
EMNLP
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Publisher:
Association for Computational Linguistics
Note:
Pages:
32207–32220
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URL:
https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.1639/
DOI:
Bibkey:
Cite (ACL):
Charles Nimo, Shuheng Liu, Irfan Essa, and Michael L. Best. 2025. Africa Health Check: Probing Cultural Bias in Medical LLMs. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 32207–32220, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Africa Health Check: Probing Cultural Bias in Medical LLMs (Nimo et al., EMNLP 2025)
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https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.1639.pdf
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