In the present study, RTc, an aqua-alcoholic extract of Tinospora cordifolia, a potential radioprotector, was evaluated for its ability to protect peritoneal macrophages (PMs) against LPS-induced death in ex vivo conditions using DNA fragmentation and survival assays. The effect of RTc on nitric oxide (NO) and TNF- production by LPS induced PMs was also assessed. The interaction of RTc with DNA (plasmid relaxation assay) and its effect on sodium nitroprusside (SNP) generated nitric oxide (NO) were also analysed. LPS induced significant DNA fragmentation in a dose dependent manner, decreased macrophage survival (48.2 ± 2.2 % of control), and increased NO (32.4 ± 1.5 ?M nitrite/106 cells) and TNF- levels (1943.4 ± 94.7 pg/ml) significantly as compared to their respective control values. Pre-treatment with RTc (-1h) decreased DNA fragmentation (13.4 ± 0.4 %), increased survival (87.5 ± 4.2 % of control), and reduced NO (18.9 ± 0.7 ?M nitrite/106 cells) and TNF- levels (418.5 ± 19.5 pg/ml) significantly. RTc also inhibited radiation-induced relaxation of plasmid DNA and significantly quenched SNP-generated NO even at low concentrations (64.6 ± 3.6 % inhibition at 2.25 ?g/ml, p ? 0.001). Such diverse effects of RTc on PMs could explain the radioprotective efficacy of this herbal extract.