灭鼠药

• 氵(water; liquid)RADICAL
• 烕(extinguish fire; put out fire)PHONETIC

Using water to extinguish fire is a complete act of destruction.

• 鼠(mouse; rat (pictographic))ASSOCIATIVE

A mouse's head, teeth, body, and tail are stylized to form this character.

• 艹(grass; plant)RADICAL
• 约(promise; bind)PHONETIC

Medicine is made from grass and plants, sounding like "wish" or "promise".