We report on eight children with severe diarrhea beginning in the first 6 months of life (< 1 month in six cases), who had a number of features in common. All were small for gestational age and had an abnormal phenotype, including facial dysmorphism, hypertelorism, and woolly, easily removable hair with trichorhexis nodosa. Two were products of consanguineous marriages. Severe secretory diarrhea persisted despite bowel rest (n = 7). Jejunal biopsy specimens showed total or subtotal villous atrophy with crypt necrosis, and inconstant T-cell activation in some cases (n = 3). Colon biopsy specimens showed moderate nonspecific colitis. All the patients had defective antibody responses despite normal serum immunoglobulin levels, and defective antigen-specific skin tests despite positive proliferative responses in vitro. Three had monoclonal hyper-immunoglobulinemia A. The course was marked by diffuse erythroderma in two cases and mental retardation in three. Treatment included bowel rest, intravenous administration of immune globulins, administration of corticosteroids (n = 6) and cyclosporine (n = 2), and bone marrow transplantation (n = 1). Five patients died between the ages of 2 and 5 years (of sepsis or cirrhosis), two are being fed enterally, and one continues to receive total parenteral nutrition. The cause of the combined low birth weight, dysmorphism, severe diarrhea, trichorrhexis, and immunodeficiency is unclear. These features may constitute a specific syndrome within the group of intractable diarrheas of infancy.