“LEGALLY BLONDE” star Reese Witherspoon raced her almost two-year-old daughter to the hospital in a terrifying medical emergency.

The beautiful actress and hubby Ryan Phillippe were panic-stricken after watching their precious Ava suddenly develop a high fever and then turn pale and listless on July 23.

“Reese and Ryan were relaxing in the early evening when Ava started acting cranky,” revealed a family insider.

“The young parents figured she was just tired and needed to go to bed, but when Reese touched her little angel’s face, she was burning up.

“Ava was crying and experiencing severe diarrhea. The little girl told Reese, ‘Mommy, my tummy hurts.’ “

The couple thought at first their daughter might have eaten something that didn’t agree with her. They tried to lower Ava’s fever with a cool washcloth and Reese rocked her in her arms.

“But Ava was getting weaker and weaker. After a few hours, they decided enough is enough. They jumped into a car and sped to Cedars-Sinai Medical Center in Los Angeles.

“Reese was so worried about Ava that she cried a soft whimper all the way to the hospital.

“Ryan reassured Reese everything was going to be O.K. And Reese reassured Ava.” But both were terrified.

“Ryan pulled up to the emergency room and ran inside with baby Ava. Reese was right behind them,” said the family insider.

“Doctors closely monitored Ava’s vital signs. They determined she had a touch of the flu or some form of indigestion. And because of the baby’s high fever and diarrhea, she was dehydrated.”

An exhausted and relieved Reese and Ryan were allowed to take their bundle of love home that night.

Reese, 25, and Ryan, 26, had butted heads in the past, because the talented actress wanted her hubby to party less and become a more active father and husband, revealed a close source.

But Ava’s medical scare had a happy, unexpected side effect, divulged the family insider.

“Not only did Ava get a clean bill of health, but the couple also bonded in a very special way. Although they’ve had their ups and downs, they want their marriage to work.

“Reese and Ryan leaned on each other in their time of need — and it served as a reminder of how deeply they love each other.”