Cut sauerkraut into small pieces.
Rinse sauerkraut in colander.
In saucepan, heat sugar, vinegar, and sauerkraut juice.
Bring to a boil, stir to dissolve sugar.
Remove from heat.
In large bowl, combine sauerkraut, carrots, celery, and onion.
Pour dressing over salad and mix.
Chill several hours to blend flavors.
