Elevated serum tumor necrosis factor alpha (TNF-alpha) levels predict mortality in patients with alcoholic liver disease. Administration of anti-TNF-alpha antibodies, obliteration of Kupffer cells or gut sterilization protect against ethanol-induced hepatocellular injury in animal models. In this study, we evaluated the in vivo efficacy of an antisense phosphorothioate oligodeoxynucleotide (S-ODN) targeted against TNF-alpha mRNA (TJU-2755). Naive rats that were administered TJU-2755 (10 mg/(kg body weight (BW)/day) for 2 days) in the free form were challenged with LPS to induce TNF-alpha secretion. Antisense TJU-2755 treatment reduced serum TNF-alpha levels by 62%. A comparison of the efficacies of mismatched and random S-ODNs with that of TJU-2755 showed that some non-specific inhibition might accompany the sequence-specific effects of TJU-2755. To optimize the targeting of the S-ODN, TJU-2755 was encapsulated in pH-sensitive liposomes for in vivo delivery to macrophages. The efficacy of liposome-encapsulated TJU-2755 was assessed in ethanol-fed animals that were administered LPS to induce liver injury. Liposomal delivery of TJU-2755 allowed a much lower dose (1.9 mg/kg BW/day, for 2 days) of the S-ODN to reduce LPS-induced serum TNF-alpha (by 54%) and liver injury (by 60%) in ethanol-fed rats. These data indicate that liposome-encapsulated S-ODNs targeted against TNF-alpha have therapeutic potential in the treatment of alcoholic liver disease.