The Danish Paediatric Society presents the first Danish definition of fetal alcohol spectrum disorders (FASD) in a new guideline. FASD is an umbrella term for conditions caused by prenatal alcohol exposure. To varying degrees, fetal alcohol damages manifest as physical defects, characteristic facial features and poor growth, as well as behavioural and cognitive disorders. It requires both somatic and psychological evaluation to identify these damages. Early diagnosis and identification of problems are important for prognosis as professional care has a positive preventive effect on comorbidities.