Correct

闹肚子

/ nàodùzi / 
Strokes

Definition

(coll.) to have diarrhea

Example

As a Verb

have diarrhoea/diarrhea; get the runs

1
Wǒ
我
tōngcháng
通常
yī
一
hē
喝
niúnǎi
牛奶
jiù
就
nàodùzi
闹肚子
  
。

I usually get the runs when I drink milk.