ulcer|ulcers

因为这个口腔溃疡，我吃东西都不香了。

I can’t enjoy my food because of this mouth ___ulcer.

医生建议他避免辛辣食物，以免加重口腔溃疡。

The doctor advised him to avoid spicy foods to prevent worsening his mouth ___ulcers.

她因为吃太多酸性食物而患上口腔溃疡。

She got a mouth ___ulcer from eating too much acidic food.