According to sources, the 36-year-old has been in the hospital for several days and will remain there till she recovers.
Reid was partying on some yachts in Saint Tropez and hitting up the town's nightlife in the days before she was hospitalized, reported TMZ Online.
In a picture taken on Tuesday, the "American Pie" actress was seen walking around holding her stomach and looking worried.
A representative for Ried could not be reached for comment.
