The Effect of Oral Administration of 9-cis β Carotene Rich Powder of the Alga Dunaliella Bardawil

Inclusion Criteria: * Written informed consent to participate in the study. * Men or women aged 18 years or older. * Electroretinogram (ERG) responses compatible with the diagnosis of Retinitis Pigmentosa Exclusion Criteria: * Current smokers. * Current use of Vitamin A/ beta carotene supplements. * Active arterial disease within 3 months of study entry such as unstable angina, myocardial infarction, transient ischemic attack (TIA), stroke, and coronary artery bypass graft (CABG) surgery. * History of malignancy, except basal or squamous cell skin carcinoma. * Pregnant women, women who are breast feeding, and women of childbearing potential who are not using chemical or mechanical contraception. * Uncontrolled hypertension defined as either resting diastolic blood pressure of \>95mmHg (taken from the mean of 3 readings) or resting systolic blood Pressure of \> 180 mmHg. * History of alcohol abuse or drug abuse, or both. * Patient plans to engage in vigorous exercise or an aggressive diet regimen. * Uncontrolled endocrine or metabolic disease. * Participation in another investigational drug study within 4 weeks of entry into this study. * Serious or unstable medical or psychological condition that, in the opinion of the investigator, would compromise the subject's safety or successful participation in the study. * Subject whose hormone replacement therapy (HRT) or oral contraceptive therapy (OCT) was initiated within the 3 month prior to enrollment.