药到病除

1. • lit. the disease is cured the moment the medicine is taken (idiom)
2. • fig. (of a medical treatment) to give instant results
3. • highly effective

     of a solution or method

Character by character

• 药(yào)leaf of the iris
• 到(dào)reach
• 病(bìng)illness
• 除(chú)get rid of