Disinfect sister ingesting a louse egg with drug (8)
I believe the answer is:
sanitise
'disinfect' is the definition.
(I've seen this before)
'sister ingesting a louse egg with drug' is the wordplay.
'sister' becomes 'sais' (I can't explain this - if you can you should give a lot more credence to this answer).
'ingesting' is an insertion indicator.
'a louse egg' becomes 'nit' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'drug' becomes 'e' (E is another name for ecstasy).
'sais' enclosing 'nit' is 'sanitis'.
'sanitis'+'e'='SANITISE'
Can you help me to learn more?
(Other definitions for sanitise that I've seen before include "block out unpleasant things" , "Make hygienic, sterilise" , "Make hygienic being in siesta" , "disinfect" , "Clean and sterilize" .)