Fibromuscular dysplasia was found in six patients (four women over 50 years, a 20-year-old man and a five-year-old girl). Angiography (in five cases performed because of a cerebrovascular accident) gave the typical appearance of "knotted string" changes in the large and medium sized arteries. With marked localized arterial narrowing treatment is surgical. Conservative treatment remains sympotomatic because the cause of the disease is still unknown. Even surgical treatment brings only sympotomatic relief and, because of the slowly progressive nature, is indicated only when there are neurological signs.