Many inflammatory disorders in the body are linked to oxidative tissue damage. Anti-oxidants that are present in many natural food sources may provide protection from such damage.

Beta carotene is an anti-oxidant vitamin present in many fruits and vegetables. The algae Dunaliella is particularly rich in beta carotene.

In this prospective trial we want to investigate whether beta carotene from Dunaliella may prevent exacerbations of Crohn's disease.

Patients with documented Crohn's disease who are at least 2 months in remission (CDAI<150) will be randomized to receive 60 mg beta carotene/day vs. placebo for 1 year.

The study medication will be taken in addition to regular treatment for Crohn's disease.

The protocol includes 5 visits (months 0, 3, 6, 9, 12). Each visit lasts 30-60 minutes and includes a brief interview, standard questionnaires, physical examination, and blood tests.

Exacerbation of Crohn's disease is defined as CDAI>150. The study hypothesis is that less patients treated with beta carotene will suffer an exacerbation than patients treated with placebo.

Inclusion Criteria:

• patients with documented Crohn's disease in remission (CDAI<150) for at least two months, age 17-75 years

Exclusion Criteria:

• active Crohn's disease (CDAI>150), partial bowel obstruction, impending surgery, pregnancy, serious other diseases