We conducted a pilot, open-label study to assess the effect of short-termβ-carotene administration (180 mg/d with meals for 4 weeks) on the plasma human immunodeficiency virus (HIV) RNA levels and CD4+ lymphocyte counts in 21 HIV-infected patients. We found that plasma HIV RNA levels and CD4+ lymphocyte counts did not change following this short course ofβ-carotene supplementation. Patients with lower serum concentrations ofβ-carotene before supplementation were no more likely to have an increase in their CD4+ lymphocyte count or plasma HIV RNA copy number than were those with higher concentrations. No correlation was found between pre- or postsupplementationβ-carotene or vitamin A concentrations and pre- or postsupplementation CD4+ lymphocyte counts or plasma HIV RNA titers. This study provides no support forβ-carotene supplementation for HIV-infected subjects with normal baseline serum levels ofβ-carotene and vitamin A.