This is understandably worrying, but in most cases it is not dangerous. If the spider was accidentally boiled in the milk, the heat would have destroyed most toxins and germs. Simply swallowing a spider does not usually cause poisoning.
Next Steps
* Observe your child for the next 24 hours.
* Encourage normal fluids and meals.
* Seek medical attention if your child develops vomiting, abdominal pain, difficulty breathing, swelling of the lips or face, excessive drowsiness, or any unusual symptoms.