To the Editor: We wish to draw attention to the health risks of a food supplement containing symphytum that is widely available in the United States. Numerous brands of comfrey–pepsin capsules and tablets are sold in herbal and health-food stores as a digestive aid. Users take them daily over long periods or even permanently. We have analyzed the pyrrolizidine content of two brands of comfrey–pepsin capsules, one brand purporting to be prepared from the leaves and the other from the roots of the comfrey plant. Alkaloids and alkaloid N-oxides were isolated by the method of Brauchli et al.,1 and the., No extract is available for articles shorter than 400 words. © 1986, Massachusetts Medical Society. All rights reserved.