Oh boy, this one is from the dark ages. So you need evidence to prove that breastmilk is not dairy. Like asking for proof that a horse is not a goat. "Find me the studies that a horse is not a goat". The first thing you should do is ask them where the proof is that you need to stop breastfeeding when the baby has diarrhea or vomiting. There ain't any. Burden of proof for the intervention, remember? Then you could continue with all the evidence of antimicrobial factors in breastmilk. There are lots of studies around. Use the Scientific American article (December 1995) for this crowd since it is not complicated. Original studies with numbers and statistics might be too difficult for this group who probably have trouble with subtle concepts like 2 + 2. Here are some articles anyway. Duffy LC, Byers TE, Riepenhoff-Talty M, La Scolea L, Zielezny M, Ogra PL. The effects of infant feeding on rotavirus-induced gastroenteritis. A prospective study. Am J Pub Health 1986;76:259-63 Hanson LA, Lindquist B, Hofvander Y, Zetterstrom R. Breastfeeding as a protection against gastroenteritis and other infections. Acta Pediatr Scand 1985;74:641-2 Ruiz-Palacios GM, Calva JJ, Pickering LK, Lopez-Vidal Y, Volkow P, Pezzarossi H, et al. Protection of breastfed infants against Campylobacter diarrhea by antibodies in human milk. J Pediatr 1990;116:707-13 Cruz JR, Gil L, Cano F, Caceres P, Pareja G. Breastmilk anti-Escherichia coli heat labile toxin IgA antibodies protect against toxin-induced infantile diarrhea. Acta Pediatr Scand 1988;77:658-62 Gillin FD, Reiner DS, Wang C-S. Human milk kills parasitic intestinal protozoa. Science 1983;221:1290-2 France GL, Marmer DJ, Steele RW. Breastfeeding and Salmonella infection. Am J Dis Child 1980;134:147-52 Haffejee IE. Cow¹s milk-based formula, human milk and soya feeds in acute infantile diarrhea: A therapeutic trial. J Pediatr Gastroenterol Nutr 1990;10:193-8 Lerman Y, Slepon R, Cohen D. Epidemiology of acute diarrheal diseases in children in a high standard of living rural settlement in Israel. Pediatr Infect Dis J. 1994;13:116-22 Howie PW, Forsyth JS, Ogston SA, Clark A, Du V Florey C. Protective effect of breastfeeding against infection. Br Med J 1990;300:11-6 Duffy LC, Riepenhoff-Talty M, Byers TE, La Scolea LJ, Zielezny MA, Dryja DM et al. Modulation of rotavirum enteritis during breastfeeding. Am J Dis Child 1986;140:1164-8 Haddock RL, Cousens SN, Guzman CC. Infant diet and salmonellosis. Am J Pub Health 1991;81:997-1000 Jones EG, Matheny RJ. Relationship between infant feeding and exclusion rate from child care because of illness. J Am Dietetic Assoc 1993;93:809-11 MacFarlane PI, Miller V. Human milk in the management of protracted diarrhea of infancy. Arch Dis Child 1984;59, 260-65 Yoshioka H, Ken-ichi I, Fujita K. Development and differences of intestinal flora in the neonatal period in breastfed and bottle fed infants. Pediatrics 1983;72:317-21 Hernell O, Ward H, Blackberg L, Pereira MEA. Killing of Giardia lamblia by human milk lipases: An effect mediated by lipolysis of milk lipids. J Infectious Diseases 1986;153:715-20 Andersson B, Porras O, Hanson LA, Lagergård T, Svanborg-Edén C. Inhibition of attachment of Streptococcus pneumoniae and Haemophilus influenzae by human milk and receptor oligosaccharides. J Infectious Diseases 1986;153:232-7 Bell LM, Clark HF, Offit PA, Slight PH, Arbeter AM, Plotkin SA. Rotavirus serotype-specific neutralizing activity in human milk. Am J Dis Child 1988;142:275-8 Schroten H, Lethen A, Hanisch FG, Plogmann R, Hacker J, Nobis-Bosch R et al. Inhibition of adhesion of S-Fimbriated Escherichia coli to epithelial cells by meconium and feces of breastfed and formula fed newborns: mucins are the major inhibitory component. J Pediatr Gastroentero Nutr 1992;15:150-8 Walterspiel JN, Morrow AL, Guerrero ML, Ruiz-Palacios GM, Pickering LK. Secretory anti-Giardia lamblia antibodies in human milk: protective effect against diarrhea. Pediatrics 1994;93:28-31 Torres O, Cruz JR. Protection against Campylobacter diarrhea: role of milk IgA antibodies against bacterial surface antigens. Acta Pediatr Scand 1993;82:835-8 Pickering LK, Morrow AL, Herrera I, O¹Ryan M, Estes MK, Suilliams SE, et al. Effect of maternal rotavirus immunization on milk and serum antibody titers. J Inf Dis 1995;172:723-8 You could further continue by stating that a study from the Hospital for Sick Children showed you don't even have to stop formula when a baby has diarrhea. See similar article by Haffejee above. Finally, you could say that Unicef and WHO have put out statements on continuing breastfeeding during diarrhea, so has the Canadian Pediatric Society, and, so, probably has the American Academy of Pediatrics. If you can't convince them with that, you don't have the persuasive powers of the formula company rep. Take them to lunch and pay for it. Jack Newman, MD, FRCPC