What are the side effects of Mabthera?

I was diagnosed with non-Hodgkin's lymphoma 4 years ago. I underwent chemotherapy with Adriamycin. Subsequently it relapsed last year and I took 6 cycles of Mabthera. Now my tests show that I am under remission. My doctor advised 600 ml Mabthera every 3 months as preventive medicine and I have been taking it. Will this affect my general health? Are there any natural ways to maintain general good health while taking Mabthera.