A presentation created and delivered by me in the pediatric department of Ibrahim Malik Teaching Hospital (Khartoum, Sudan) on the 10th of May 2017. It is composed of the following parts: - Definition - Epidemiology - Causes - Assessment - Management The total number of slides is 19 slide. One of the slides contain a video from the IMCI program by World Health Organization (WHO) for assessment of children with dehydration. The youtube link of the video added in this online version instead of the complete video that was shown in the original presentation.