The most common and most likely answer to this crossword clue is the 8 letter word MAGNESIA
I've seen this crossword clue in The Guardian
M
A
G
N
E
S
I
A
More clues leading to the result MAGNESIA
- Stomach calmer, perhaps one manages to regroup
- Lady’s boring design, flipping tasteless white stuff
- Enigma resolved by a cure for indigestion
- Laxative one girl fed to another
- End up with girl getting covered in powder
- This powder? Somehow manages to get one settled inside
- Without first ingredient, mismanage dissolving powder
- Chemical from polished asian gem
- Its milk may pulverise Asian gem
- White chemical substance derived from Asian gem
Buddy explains!

The straight part
We know that "tasteless white stuff" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tasteless white stuff = magnesia.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MAGNESIA mean?
MAGNESIA noun- Magnesium oxide