Adriamycin (ADR) belongs to anthracycline group of antibiotics, which is widely used for the complete remission of solid tumours. In carcinoma breast, non Hodgkin's lymphoma and Hodgkin's lymphoma, ADR is considered as most useful chemotherapeutic medication. Anthracycline by virtue of their quinone group generates free radicals in solution in both normal and malignant cells. The Ocimum leaf extract as well as their flavonoids orientin and vicenin have strong antioxidant activity in vitro and antilipid peroxidative effect in vivo, and strongly suggest free radical scavenging as a major mechanism by which Ocimum products protect against cellular damage and tumour induction. However, most interest has been devoted to the antioxidant activity of flavonoids, which is due to their ability to reduce free radical formation and to scavenge free radicals. The capacity of flavonoids to act as antioxidants in vitro has been a subject of several studies in the past years. The antioxidant efficacy of flavonoids present in Ocimum sanctum in vivo is less documented, presumably because of the limited knowledge on their uptake in tumours. Inspite of limitation of the knowledge of exact mechanism of uptake of flavonoids we have studied antioxidant efficacy of Ocimum sanctum aqueous extract (140mg) with placebo control in carcinoma breast, non Hodgkin's lymphoma, Hodgkin's lymphoma cases along with chemotherapy particularly during third cycle. Statistical analysis has been done by Mann Whitney's test which shows no significant difference of antioxidant enzymes between study (n=19) and control (n=16) group before chemotherapy. There is a significant increase of all scavenging enzymes in study group (n=19) compared to control group (n=16) after chemotherapy. Significant increase in the Haemoglobin content and enhanced activities of Superoxide dismutase (SOD) and Catalase (CAT) in the study group which was given Ocimum.