Abstract:Objective: To study and compare the differences in how ChatGPT O1 and Claude 3.5 Sonnet answer common questions related to unicentric Castleman disease in the neck. Method: A total of 36 common questions related to unicentric Castleman disease of the neck were entered into the ChatGPT o1 and Claude 3.5 Sonnet search engines. The professor of otorhinolaryngology–head and neck independently evaluated the responses generated by ChatGPT o1 and Claude 3.5 Sonnet, assessing their readability,accuracy,quality, understandability, and practical applicability. Result: Regarding readability, Claude 3.5 Sonnet generated significantly more concise responses across all categories (189.36 ± 69.09 vs. 381.56 ± 153.28 characters, P=1.9×10?7), had lower reading scores (1.68 ± 5.64 vs. 11.20 ± 11.16, P=1.4×10?7) and exhibited higher grade-level scores (54.93 ± 35.81 vs. 16.70 ± 2.03, P =5.5×10?13). In terms of understandability and actionability as measured by PEMAT-P scores, Claude 3.5 Sonnet demonstrated higher overall understandability (0.38 ± 0.17 vs. 0.06 ± 0.05, P=2.3×10?5) and actionability (0.25 ± 0.22 vs. 0.08 ± 0.09, P = 1.5 × 10?2). Nevertheless, ChatGPT-o1 recorded a higher overall accuracy score (4.88 ± 0.28 vs 4.58 ± 0.37, P =2.2 × 10-3) and attained a superior quality rating under the revised EQIP standards (7.47 ± 1.28 vs 5.75 ± 1.20, P=2.2×10?9). Conclusion:Claude 3.5 Sonnet is superior in conciseness, understandability, and actionability, whereas ChatGPT-o1 is stronger in terms of accuracy, overall quality and readability.