The antimalarial efficacy and safety of mechanically induced solventlessly synthesized lumefantrine-copper complex were investigated in experimental mice. Parasite level in Plasmodium berghei-infected mice treated with lumefantrine - copper complex (LCC) significantly declined (p < 0.05) at day 3 and was comparable with that of chloroquine-treated mice. LCC attained a percentage chemo-suppression which was significantly higher than those of pure lumefantrine and comparable with chloroquine. Pure lumefantrine attained a clearance of 88.52%, chloroquine was 91.95%, while LCC was 95.10%. Administration of lumefantrine, LCC and chloroquine to mice for 7 days caused a significant increase (p < 0.05) in the activities of alkaline phosphatase, acid phosphatase and lactate dehydrogenase in the liver when compared with the control, and a significant reduction (p < 0.05) in the liver and kidney activities of alanine and aspartate aminotransferases when compared with the control. Also, there was a significant decrease (p < 0.05) in the levels of PCV, Hb, RBC and lymphocytes and a significant increase (p < 0.05) in the white blood cells count and neutrophil counts in all the treatment groups when compared with control. Alterations in the biochemical parameters and chromosomal aberration in the organs investigated suggested selective, chromosomal and functional toxicity of the tested drugs.