The most common and most likely answer to this crossword clue is the 8 letter word LAUDANUM
I've seen this crossword clue in The Daily Telegraph
L
A
U
D
A
N
U
M
More clues leading to the result LAUDANUM
- Approve a new, er, drug
- Numbers following inverse of a binary number
- Obsolete medicine getting praise with an expression of uncertainty
- Praise article on socially acceptable male drug
- Praise a group of underground workers finding drug
- Praise a book on making a drug
- Praise addict initially almost insensible from narcotic
- Some applaud a number a number
- Praise a union — medicine no longer dished out?
Buddy explains!

The straight part
We know that "drug" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case drug = laudanum.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 LAUDANUM mean?
LAUDANUM noun- A tincture of opium, once widely used for various medical purposes and as a recreational drug.
- To add laudanum to (a drink or the like).
- To cause (a person) to be high on laudanum.