Capture stress syndrome (CSS) is a potentially fatal condition associated with capture or transport of sea otters and other animals. Pursuit, capture, transport, and chemical immobilization of otters can result in CSS. Clinical manifestations of CSS in sea otters include refusal of food, shivering, absence of grooming or grooming restricted to the muzzle and upper chest, matted pelage, rigid posture, floating motionless on back, rear limbs elevated, rear limbs crossed or folded tightly across lower abdomen, forelimbs in rigid "praying hands" posture, lack of responsiveness to other otters, and continuous vocalization. Gastric ulceration, gastroenteritis, and hemorrhagic adrenal cortex are evident at necropsy or through histopathology. Treatment consists of fluid therapy (subcutaneous, intraperitoneal and intraosseous) antibiotics, vitamins, cimetadine and dexamethasone. Prevention is the key to healthy otters.