贝赛特氏症（Behçet / Behçet's disease），或称贝歇氏病 (Behçet's syndrome)、白赛病 (Morbus Behçet)、贝赛特氏症候群 (Behçet-Adamantiades syndrome)，或贝赛特氏综合症，因多发于丝路国家，故亦称丝路病。它是一种罕见的免疫系统的微血管系统性血管炎，此症会造成各种溃疡及眼睛视觉的问题，20至40岁的青壮年人较易发病。

贝赛特氏症（BD），于1937年被土耳其的皮肤科医生贝赛特（Hulusi Behçet）而命名，他首先发现了因基因问题引起的自体免疫异常而致病，主要症状为：反复性口腔溃疡（recurrent oral ulcers）及口疮三重复合症、反复性生殖部位溃疡（recurrent genital ulcers）及 葡萄膜炎（uveitis）。这是一种系统性疾病，它牵涉的内脏器官包括胃肠道、肺动脉、肌骨骼、心血管和神经系统。由于此症可影响几乎人体内的每个器官，其他情况如血管炎，纤维肌肉痛、偏头痛或中枢神经系统的问题、视力问题、心跳过速和关节疼痛，肿胀通常也与贝赛特氏症有关。

Behçet's disease or Behçet disease (/bɛˈtʃɛt/), sometimes called Behçet's syndrome, Morbus Behçet, Behçet-Adamantiades syndrome, or Silk Road disease, is a rare immune-mediated small-vessel systemic vasculitis that often presents with mucous membrane ulceration and ocular problems. Behçet's disease (BD) was named in 1937 after the Turkish dermatologist Hulusi Behçet, who first described the triple-symptom complex of recurrent oral aphthous ulcers, genital ulcers, and uveitis. As a systemic disease, it can also involve visceral organs such as the gastrointestinal tract, pulmonary, musculoskeletal, cardiovascular and neurological systems. This syndrome can be fatal due to ruptured vascular aneurysms or severe neurological complications.