OBJECTIVES: To assess the toxicity profile and pharmacokinetics of BAY 43-9006 at oral dose regimens of 200 mg once daily, 200mg twice daily, or 400 mg twice daily, up to the toxic dose, in patients with HIV-associated Kaposi s sarcoma (KS) who are receiving ritonavir. Also, to assess in a preliminary manner the pharmacokinetics and toxicity profile of BAY 43-9006 in patients who are not receiving ritonavir.