In China, some food can be really spicy, mouth burning spicy. So, if you don't fancy spicy food, you'd better check before you have it.

You can ask the waiter or your friend '这个辣吗？' , meaning 'is this spicy?'. The pronunciation is 'zhè gè là ma ？'.
辣 ( là ) means spicy.

If the answer is 辣 ( là ) or 很辣 (hěn là ), you may want to avoid it.

Some restaurants may mark the spicy level for each dish. The level is often divided into 不辣(bú là) 微辣 (wēi là), 中辣 (zhōng là), 极辣 (jí là).
不辣(bú là) means not spicy
微辣 (wēi là) means a bit spicy
中辣 (zhōng là) means spicy
极辣 (jí là) means very spicy