One of the outstanding characteristics of many patients with beriberi is cardiac insufficiency. This type of cardiac insufficiency is caused by changes in the cardiovascular system which are dependent on a deficient diet. The deficiency has been shown to be due to a lack of vitamin B. In this paper, I wish to present the results of a study of two groups of patients with beriberi, directing special attention to the cardiovascular system. I shall emphasize and discuss certain differences that are present. In the first group of fifteen patients, cardiac insufficiency was demonstrated, and in the second group of twelve patients no obvious symptoms of cardiac insufficiency were observed. PATHOLOGIC CHANGES IN BERIBERI The papers of Pekelharing and Winkler,1 Nocht,2 Muira,3 Vedder,4 Kasuma,5 Herzog6 and Scheube7 may be consulted for a detailed description of the pathologic changes occurring in beriberi. For the purpose of this paper, the main pathologic