Pathology
- seborrhoea
- Seizures
- Selective mutism
- senility
- Sensory integration disorder
- Sepsis
- septic
- septicemia
- Serum sickness
- Severe Acute Respiratory Syndrome (SARS)
- Severe Combined Immune Deficiency
- Severe combined immunodeficiency
- Shaken baby syndrome
- Shamanism
- Shin splints
- shivering
- shock
- Siamese twins
- Sick building syndrome
- sickle cell disease