SUMMARY Background: IMCI ( Integrated Management Childhood Illness) is a sort of strategy for childhood attention that aims to reduce mortality by prevalent diseases in population below 5 years old. In acute diarrhoea the IMCI’s preventive activities are to promote the maternal knowledge about danger signs, to look for opportune care and to improve oral hydration therapy (ORT). Objectives: To establish maternal knowledge about children’s danger signs in acute diarrhoea below 5 years old. To determine hydration practices in acute diarrhoea. Methods: A descriptive study was carried out in Hospital del Norte of Popayan, Colombia, first level of attention health centre for establishing mother’s knowledge of danger signs in acute diarrhoea. A survey based of an instrument from IMCI to 204 mothers chosen consecutively was applied. Variables measured were: maternal age, sex, child age, region (urban-rural), socioeconomic status, bond to the Colombian Social Security National System, scholarship, number of sons, coexistence with partner, coexistence with child’s grandmother. The knowledge variable was determined from a dichotomy way. The mother’s knowledge was established