You can avoid nausea by preparing for the flush better. I recently flushed and it was my first one since the beginning of the year and I had no nausea whatsoever.
The trick is colon cleansing a head of time... A week or so of something like Oxypowder or Psylium or even a laxative tea.
And staying hydrated. Drinking a lot of water even after you drink the epson salts. Dehydration causes nausea since you need it to keep the toxins flushing out.
Eat light on the day of the flush..All I eat is fruit since it digests quickly.
I wouldn't add ginger to the OO (Olive-Oil) mix...If you *have* to then I'd say take it a couple hours after you drink the OO/GF. Healthfood stores sell ginger in capsules and other herbs for nasuea.