We studied the effects of ion cyclotron resonance (Seqex) magnetic therapy on the blood of thirty two healthy volunteers. They received 15 treatments each 27 minutes in length, distributed over 5 weeks. The concentrations of two blood components, malondialdehyde (MDA) and cholesterol were measured in each subject, immediately before and immediately after the 15 treatments as well as one month after the final treatment. Highly significant reductions in MDA concentrations, averaging 53.8% were noted just after the 15 treatments, tending to return to the original concentrations one month later. The effect on HDL and LDL cholesterol levels were not significant. The implication of this work is that this type of therapy may be useful in dealing with oxidative stress.