Most vomiting in children age 3 and younger is caused by a viral stomach flu. With home treatment, vomiting usually will stop within 12 hours. If your child has a more serious illness, he or she usually will have other symptoms in addition to vomiting. These symptoms include:

• Severe pain.
• Bulging soft spot on a baby's head (when the baby is not crying).
• Drooling and trouble swallowing.
• New swelling, pain, redness, or warmth in one or more joints.
• Rectal temperature of 105°F (40.6°C) or higher.
• Severe neck stiffness or pain and fussiness.
• Skin rash or severe bruises.
• Frequent urination or pain and burning with urination. These may be signs of a urinary tract infection.
• Very rapid, difficult breathing.
• A child who is very sleepy or hard to wake up.

Immediate medical care is needed if your child is vomiting and has other signs of serious illness.