The purpose of the present study is to evaluate the antitumor activity (ATA) of traditional herbal preparation Sivanar Amirtham (SA) on Dalton’s Lymphoma Ascites. Siddha medicine system (SMS) is a traditional system of medicine originated from ancient Tamilakam of South India. Siddha medicine is a traditional healing system from Tamilakam in ancient South India. For our purpose, we have performed acute toxicity (AT) study as per OECD guidelines 423 and ATA by xenograft method. In this study, a single dose of 300, 1000 and 2000 mg/kg of Sivanar Amirtham suspension (SAS) was orally (p.o.) administered in mice and animals were observed for 14 days. For antitumor study (ATS), we have used DAL cells which were intraperitoneally (i.p.) inoculateded into mouse. The ATAs were studied by monitoring the parameters such as cell growth inhibitors, tumor weight measurements, mean survival time of DAL bearing mice as well as changes in depleted haematological and biochemical parameters due to tumorigenesis. The SAS was also evaluated for in vitro cytotoxicity study in different concentration and the viability of cells was determined by exclusion method of trypan blue dye (TBD). The AT study showed no signs of toxicity and no mortality after single administration of SAS. SAS caused significant decrease in packed cell volume (PCV) (value), Tm volume (value) and viable cell count (value), and it prolonged the life span of DAL Tm carrying mice. Haematological and biochemical profiles were reverted to normal levels in SAS treated mice. The results of in vitro cytotoxicity show that SAS showed significant ATA in mice with moderate DAL levels. The IC50 value turned into discovered to be 800 μg/ml from the in vitro cytotoxicity examine. The study strongly suggests that SAS has the potential to be an antitumor medication against DAL cells induced Tm and it can be extrapolated for further cancer (CA) prevention applications.