The Modern Family star's son, Gus, was admitted to Santa Barbara's Cottage Hospital.
The four-year-old had appendicitis, a condition quite rare with children that young.
"A heartfelt thanks to the docs and nurses at Cottage Hospital. Gus is an appendix lighter but well on the mend," Julie wrote her Twitter followers. "We are grateful.
Gus is one of Julie and her husband Scott Phillips' three sons. They have a vacation home in the Santa Barbara area and were there when Gus had his appendix attack.
The Emmy-winning sitcom star knows something about medical emergencies.
She's worn a pacemaker since her 20s because of a heart condition.
And as RadarOnline.com reported, her oldest son, Oliver, went into anaphylactic shock and nearly died when he was just two years-old and was stung by a bee.