In infants, failure to grow according to health standard norms for linear growth, weight, and head circumference. Also called weight faltering, signs include poor feeding, poor sucking, and weak cry. Causes include swallowing difficulty, anorexia, neuromuscular dysfunction, cleft palate, parental neglect, malnutrition, malabsorption, gastrointestinal abnormality, infection, parasite, or genetic or systemic illness causing impaired nutritional intake and abnormally slow growth, or lack of growth.

An infant with failure to thrive syndrome may face severe malnutrition, dehydration, and permanent damage to brain, central nervous system, and organs, constituting a medical emergency.

If untreated, prognosis may be poor. Management involves identifying and treating the underlying causes, and symptomatic interventions.