The most common and most likely answer to this crossword clue is the 6 letter word DROPSY
I've seen this crossword clue in The Times
D
R
O
P
S
Y
More clues leading to the result DROPSY
- Falls down with unknown ailment
- A little fluid, say, not a condition full of it
- Medic works on last bit of nasty complaint
- Medical problem declines with ending of puberty
- Medic leading operation on extremely squidgy swelling
- Works in arid condition
- Medic works on variable accumulation of fluid
- Malaise leading to butterfingers?
- Swelling comes down over the years
- Swelling reduces by day's end
Buddy explains!

The straight part
We know that "ailment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ailment = dropsy.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 DROPSY mean?
DROPSY noun- Swelling, edema, often from chronic obstructive pulmonary disease (COPD).