DE will work on intestinal parasites, but not parasites in organs of the body.
Before going too far with trying to kill parasites it is a good idea to make sure you have them. Many of the herbs used to kill parasites have thier own toxicity. Wormwood for example is effective against liver flukes, although it is also a neurotoxin. You have to be very careful about using it in high doses or for extended periods of time.
If you are not sure if you have parasites there are some herbs you can take that kill parasites and are still safe. These include raw pumpkin seeds, papaya seeds and elecampane root (also considered excellent for liver flukes). The raw pumpkin seeds you can munch on throughout the day. Papaya seeds or elecampane I recommend a tablespoon three times daily for 30 days.