This document provides an overview of severe acute malnutrition (SAM). It begins with definitions of malnutrition and indicators used to measure it. SAM is defined as very low weight-for-height, mid-upper arm circumference below 115mm, or nutritional edema. The major forms are marasmus and kwashiorkor. Epidemiology data shows millions of children worldwide suffer from SAM. Causes include insufficient food intake, poor nutrition during pregnancy and breastfeeding, and infectious diseases. Diagnosis involves assessing weight-for-age, mid-upper arm circumference, and presence of edema. Treatment follows three phases- stabilization, transition, and rehabilitation-with feeding protocols, infection treatment, and micronutrient supplementation. Prevention