The reported side effects of Cancell/Cantron/Protocel include temporary, moderate fatigue during the first few weeks of treatment and nausea. Reviewed in [1,2] One patient who exceeded the manufacturer's dose recommendations experienced diarrhea for a few hours but was reported to be fine the next day. Reviewed in 
Questionable methods of cancer management: Cancell/Entelev. CA Cancer J Clin 43 (1): 57-62, 1993 Jan-Feb.
Cancell Alternative Cancer...