Large Language Models in Medicine: Clinical Applications, Technical Challenges, and Ethical Considerations

1) Summarization

LLMs have demonstrated effectiveness in summarizing lengthy clinical texts. Specific applications include condensing progress notes into problem lists, abstracting findings from radiology reports into concise impressions, generating after-visit summaries from detailed history and physical examination notes, summarizing physician-patient dialogues, and shortening extensive patient-generated health questionnaires [14,15]. Research using models such as GPT-4 indicates that LLM-generated summaries can match or even surpass human-produced summaries in completeness and accuracy for particular tasks, while accomplishing this significantly faster [15].

2) Note generation/drafting

LLMs can assist in drafting various clinical documents, including discharge summaries [14], referral letters, and inter-unit handoff notes [16]. Additionally, LLMs can identify goals of care conversations within electronic health record (EHR) notes and rapidly generate clinically useful summaries. Importantly, the reported incidence of hallucination (incorrectly generated content) for this specific task is notably low [17].

3) Information extraction

These models can extract structured data elements (e.g., diagnoses, medications, symptoms, patient-reported outcomes) from unstructured narrative text within EHRs or other clinical documents [18]. This capability facilitates data aggregation for quality improvement initiatives, research purposes, or populating structured fields in EHRs.

4) Documentation improvement

LLMs may also analyze clinical documentation to identify missing information, inconsistencies (e.g., discrepancies between diagnosis and treatment plan), or areas requiring clarification, thereby improving the overall quality and accuracy of medical records [19].

1) Generation of differential diagnoses

LLMs can evaluate patient symptoms, medical history, and preliminary test results to suggest potential differential diagnoses to clinicians. Studies have shown that LLMs can outperform clinicians in generating differential diagnoses and in the quality of diagnostic and management reasoning, especially when employing a chain-of-thought (CoT) process that mirrors human clinical reasoning [20–22]. Thus, LLMs hold potential to enhance diagnostic accuracy and efficiency, particularly in complex clinical scenarios.

2) Answering clinical questions

LLMs function effectively as advanced information retrieval systems capable of answering specific clinical queries by integrating information from medical knowledge bases, scientific literature, or clinical guidelines [8,23,24]. Systems like Med-PaLM 2 have demonstrated strong performance on clinical knowledge assessments analogous to medical licensing examinations (e.g., the MedQA benchmark), achieving accuracy levels comparable to or exceeding those of human experts in multiple studies [9].

3) Interpretation of complex clinical data

LLMs show emerging capabilities for interpreting complex clinical data, potentially integrating information across multiple modalities (e.g., textual reports and imaging findings). Current research involving multimodal models such as Med-PaLM M and Med-Gemini explores these promising opportunities [23,25]. Such interpretation capabilities could also assist in treatment planning decisions [17,26].

Nevertheless, translating these capabilities into reliable clinical decision support (CDS) remains challenging. Although strong performance on standardized assessments is reassuring, studies simulating real clinical scenarios have identified significant deficiencies [27]. A notable gap persists between performance on knowledge-based tests and the nuanced, context-dependent judgment essential for clinical practice. Current LLMs excel at information retrieval yet lack the sophisticated clinical judgment and integrative capacities of human clinicians [28]. Moreover, seamless integration with clinical workflows and EHR systems, which would be essential for successful CDS, remains difficult to achieve [29].

1) Simplifying of medical information

LLMs can translate complex medical terminology (e.g., informed consent documents) [30,31], research findings (e.g., clinical trial summaries) [32], or clinical reports (e.g., discharge summaries) [6,33] into straightforward language that patients can easily comprehend. This application has significant potential to enhance patient understanding and promote effective shared decision-making.

2) Patient question answering/chatbots

Virtual assistants or chatbots powered by LLMs can respond to patient inquiries regarding health conditions or treatments, offering preliminary information and guidance [34]. Remarkably, LLMs can deliver responses with a significant degree of empathy, even being perceived by patients as more empathetic than human clinicians in certain written communications [22,35].

3) Increasing health literacy

By generating clear, understandable, and personalized health information, LLMs have the potential to enhance patients' overall health literacy [36].

Despite this promise, caution is warranted. LLMs can produce inaccurate or misleading information (misinformation), lack nuanced understanding of individual patient circumstances, and fail to convey critical emotional and psychological dimensions inherent in patient care. The impersonal nature of chatbot-mediated communication cannot replicate the therapeutic benefits of direct human clinician-patient interactions. Thus, employing LLMs for patient communication necessitates careful oversight and rigorous validation of information for accuracy and appropriateness.

1) Accuracy and reliability

Ensuring the accuracy and reliability of LLM outputs in clinical contexts—where errors carry severe consequences—is arguably the most critical technical barrier. LLMs are known to “hallucinate,” generating fluent, plausible-sounding content that is factually incorrect, unsupported by source data, or entirely fabricated [37–40]. If relied upon for clinical decisions, these inaccuracies directly threaten patient safety. Mitigation strategies currently explored include retrieval augmented generation (RAG) to ground responses in external knowledge sources, improving uncertainty estimation and calibration techniques, employing specific prompting strategies such as chain-of-thought, domain-specific fine-tuning, implementing domain-informed safety guardrails, and developing robust hallucination detection methods [41].

Beyond complete fabrication, LLMs can produce outputs that contradict source data or established medical facts or omit critical details from summaries and analyses [16]. These errors also present substantial patient safety risks.

2) Validation and evaluation

Assessing the clinical utility and safety of LLMs is exceptionally challenging. Current validation methodologies often fall short.

Standard natural language processing (NLP) evaluation metrics—such as ROUGE and BLEU for summarization tasks, or accuracy metrics for question-answering—frequently correlate poorly with clinical relevance, factual correctness, or patient safety [42]. High benchmark scores do not necessarily equate to competence in real-world clinical reasoning. Therefore, there is an urgent need for standardized, clinically meaningful benchmarks and evaluation frameworks specifically designed for medical LLMs.

An additional challenge is the rapid evolution of models and reporting standards. The swift pace of LLM development complicates timely, rigorous evaluations, as models are continually updated, potentially altering their performance characteristics. Transparent reporting standards, such as the proposed TRIPOD-LLM and MI-CLEAR-LLM guidelines [43,44], are thus essential for proper appraisal and reproducibility of studies.

3) Data quality and privacy

Training and fine-tuning LLMs require extensive, high-quality data, the availability of which is often limited [2,3]. Protecting patient privacy is equally critical. Using patient data for model training can result in data memorization, leakage, or risks of re-identification [18]. Mitigation strategies include employing synthetic data, data anonymization, pseudonymization, differential privacy techniques, robust cybersecurity measures, model penetration testing, and implementing transparent patient consent processes [45,46].

4) Integration and interoperability

Successful implementation of LLMs depends heavily on seamless integration with existing clinical workflows and healthcare IT infrastructures, particularly EHRs [11]. This presents a considerable technical challenge, requiring extensive customization and interface development. User-friendly interfaces are essential for widespread clinical adoption.

5) Transparency and explainability

LLMs generally function as “black boxes,” making it challenging to understand how specific outputs or suggestions are derived [47]. This lack of transparency discourages clinician trust, complicates error analysis and validation, and hinders informed acceptance. Developing and applying explainable AI (XAI) methods—such as SHAP [48] attention visualization [48], and integration with knowledge graphs [49]—tailored for medical LLMs is an active area of research, along with promoting transparent reporting practices.

1) Algorithmic bias and equity

A major ethical concern is that LLMs trained on datasets reflecting existing societal inequities may amplify biases in healthcare delivery [36]. This could result in poorer performance or unfair clinical recommendations for underrepresented racial or ethnic groups, gender groups, socioeconomic populations, or linguistic minorities. Linguistic bias is especially relevant, as most models are primarily trained on standard English, resulting in diminished performance for non-English speakers or users of non-standard dialects [50]. Mitigation requires intentional curation of diverse and representative training data, the development of bias detection and mitigation algorithms, validation across diverse demographic groups, and inclusive design and evaluation processes. Addressing bias is both ethically imperative and essential for clinical validity, as a biased tool cannot reliably serve all patients.

2) Patient safety and liability

LLMs’ potential to produce inaccurate information—including hallucinations, factual errors, or critical omissions—constitutes a direct risk to patient safety, potentially causing erroneous diagnoses or treatment delays. Determining responsibility or liability when an LLM contributes to clinical errors is complicated [51,52]. Questions arise about whether liability rests with the clinician using the tool, the developers, the implementing institution, or a combination thereof. The absence of definitive regulatory guidelines and established legal precedents for AI-related medical errors creates uncertainty and may impede implementation. Thus, explicit guidelines, clear accountability mechanisms, and possibly new legal frameworks are essential.

3) Data governance and consent

Using large volumes of patient data for LLM training and operation raises significant governance challenges [29,53]. Ethical data sourcing, patient privacy, data security, and obtaining valid informed consent for data use are critical concerns. Issues around data ownership and patient rights concerning data used by AI systems must be clearly addressed.

4) Transparency and trust

The inherently opaque “black box” nature of most LLMs undermines trust among clinicians and patients. Without the ability to understand or explain an LLM’s reasoning behind recommendations, clinicians are less likely to trust or confidently utilize these tools. This mistrust could result in delayed or incorrect clinical decisions, negatively impacting patient care [54]. Advancing explainability and promoting open reporting are crucial steps toward establishing trust.

5) Impact on clinician-patient relationship

Integrating LLMs into clinical interactions carries the risk of depersonalizing care, reducing clinician empathy, or negatively affecting direct communication if poorly implemented. Over-reliance on LLMs could potentially deskill clinicians or diminish their critical-thinking abilities. Conversely, by reducing administrative burdens, LLMs might enable clinicians to spend more meaningful time interacting directly with patients [55]. Careful consideration of workflow integration and human factors is required to ensure technological support enhances rather than detracts from therapeutic relationships.

6) Equity of access

Ensuring equitable access to the benefits of LLM technology across diverse patient populations, socioeconomic groups, and healthcare settings—including low-resource environments—is a significant ethical consideration [29,54]. The digital divide and disparities in technology access could exacerbate existing health inequities unless proactively addressed.

1) Rigorous validation

There is an urgent need for developing and adopting standardized, clinically meaningful validation methodologies and benchmarks. Such frameworks should accurately assess performance, safety, and real-world clinical utility, extending beyond traditional NLP evaluation metrics. Conducting prospective, randomized controlled trials comparing LLM-assisted workflows with conventional care is essential to establishing genuine clinical efficacy.

2) Technical advancement

Continued research is necessary to enhance model accuracy, minimize the frequency and consequences of hallucinations, improve robustness across diverse datasets and scenarios, and develop effective explainability techniques specifically tailored to clinical users. Further investigation into emerging ecosystems—in which multiple specialized AI agents (e.g., diagnostic agents, documentation agents, patient communication agents) collaborate by exchanging information and coordinating tasks within complex clinical workflows—is also warranted [56,57]. Active research areas additionally include integrating multimodal data [58,59] and extending LLM capabilities into physical systems [60].

3) Bias mitigation

Proactive strategies for identifying, measuring, and mitigating biases in training datasets and model outputs are crucial to ensure equitable performance across patient populations and prevent exacerbating existing health disparities.

4) Ethical and regulatory frameworks

Establishing clear ethical guidelines, robust regulatory oversight, and well-defined accountability structures is essential to govern the responsible development, deployment, and clinical use of LLM technologies in healthcare.

5) Human-AI collaboration

Research should prioritize optimizing human-AI interaction models, designing intuitive interfaces, and understanding how to best integrate LLMs into clinical workflows to effectively support clinicians rather than hinder their performance.