Hispanics in the United States have a disproportionately high risk for non-insulin-dependent diabetes mellitus (type 2 diabetes) compared with non-Hispanic whites. Little is known of the attitudes and beliefs about diabetes in this group. Using data from six focus groups of 42 Mexican Americans (14 men and 28 women), we characterized perceptions about the causes of and treatments for type 2 diabetes. Many participants believed diabetes is caused by having a family history of the disease, eating a diet high in fat or sugar, and engaging in minimal exercise. Experiencing strong emotions such as fright (susto), intense anger (coraje), or sadness and depression (tristeza) was also thought to precipitate diabetes. Nearly all participants expressed the belief that it is important to follow doctors' recommendations for diet and exercise, oral medication or insulin; many also cited herbal therapies, such as prickly pear cactus (nopal) and aloe vera (savila) as effective treatments. These findings may be useful in designing interventions to reduce the burden of diabetes in Hispanic populations.