Clue: It's used to treat throat pain, pad once inserted (7)
Answer: PROBANG
Explanation: Definition: It's used to treat throat
**PANG** ("pain") with **ROB** ("pad once") *inserted* 
 
 
"Pad" is an archaic term for robbing someone on foot (cf "footpad").
 
 
 
*A probang is a long flexible tube, often with a sponge attached to the end so that medication can be applied