Correct

药效

/ yào xiào / 
Strokes

Example

As a Noun

potency/effect of a drug; drug effect/action

1
Yàoxiào
药效
hěn
很
hǎo
好
  
。

The medicine is very effective.

2
Shīqù
失去
  
/
zēngjiā
增加
yàoxiào
药效

lose/increase a drug's potency