这个词是什么意思？
A carotenoid that is a precursor of VITAMIN A. Beta carotene is administered to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (PORPHYRIA, ERYTHROPOIETIC).
中文名称索引；定义为 MeSH 英文原文，尚未逐条译审。MESH:D019207 · MeSH 2026。
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