When is diarrhoea in an adult serious enough to need help?

Most cases settle in two to three days with fluids. Seek care for: blood or mucus in stools, fever above 102F, signs of dehydration such as very dark urine, passing urine rarely, dizziness on standing or a dry mouth, severe abdominal pain, symptoms beyond three days, or any diarrhoea following recent antibiotics. Oral rehydration salts are far better than plain water because they replace sodium and potassium too; sugary soft drinks make things worse. Anti-motility medicines should be avoided if there is fever or blood, as they can trap the infection.