OBJECTIVE: To understand maternal conceptions of infantile diarrhea, encouraging reflection on the importance of communication between mothers and health services. METHODS: Survey carried out in selected areas of six towns in the state of Pernambuco, all of which participated in the diarrhea control project coordinated by the State Health Secretariat. The information was obtained through interviews with 770 mothers, producing a representative sample of 1,026 children younger than five years. RESULTS: In general, mothers associated the occurrence of diarrhea with some kinds of food (fatty or undercooked). Better educated mothers, regardless of their place of residence, attributed it to improper hygiene and sanitation, whereas illiterate and poorly educated mothers, from the metropolitan region of Recife, blamed it on hot weather, and those living in the countryside believe the occurrence of diarrhea is related to teething. Circa 24.2% (63.4% living in the countryside) do not know how to prevent the disease. The two preventive measures most frequently adopted consist in drinking treated water and cooking food thoroughly. Only 0.5% mentioned breast-feeding. The number of children still alive and their ages influence maternal conceptions. The main sources of information about the prevention of diarrhea are the support network (45.5%), the health sector (35.9%) and the media (33.2%). CONCLUSIONS: The insufficient participation of the health sector in the information network about diarrhea, misinformation, and sharp disagreement over maternal conceptions and technical knowledge, which are the cornerstone of institutional measures, show that it is necessary to value the communicative dimension of the educational approach in child care.