I tried food-grade DE in the hope that it would deal with a chronic (30 yr) bowel complaint, for which the doctor had no remedy. It worked straight away.
Now I use just a couple of teaspoons a week mixed well in foods like hummus or mashed potato. It is practically tasteless and makes no difference to these foods. Sometimes I drink a spoonful shaken well in a little water.
I think it may be harmful if used dry or inhaled - so just don't do that!