Pode ser perigoso

Using this phrase is incredibly simple. It functions just like the English equivalent. You can use it as a standalone warning. You can also attach it to a specific action. For example, Pode ser perigoso andar sozinho à noite. You don't need complex conjugations here. The verb poder (can/may) stays in the third person singular. It is a very 'plug and play' expression for your daily life.

You will hear this everywhere in Brazil or Portugal. Use it when a friend suggests a shortcut through a dark alley. Use it when a colleague wants to skip a security protocol. It is great for texting when someone sends a suspicious link. It works perfectly at a restaurant if the food looks undercooked. It is a polite way to voice concern without being bossy.

Do not use this for things that are definitely safe. If you use it for a tiny paper cut, you'll sound dramatic. Avoid it in high-stakes emergencies where you need to shout 'Stop!' or 'Watch out!' In those cases, use Cuidado! or Pare! instead. Pode ser perigoso implies a possibility of risk, not an immediate catastrophe. Don't use it to describe a person's character unless they are literally a threat.

Portuguese speakers tend to be quite expressive about safety and health. There is a cultural habit of 'prevenção' (prevention). You will often hear grandmothers or 'tias' saying this about the wind or cold water. They might say Pode ser perigoso about drinking juice after eating grapes. It reflects a culture that values looking out for one another's well-being. It is a sign of caring, not just a cold warning.

You can spice it up to change the intensity. Pode ser muito perigoso adds emphasis. If you want to sound more casual, try É meio perigoso (It's kind of dangerous). In a formal setting, you might hear Pode representar um perigo. If you are talking about a specific person, you say Ele pode ser perigoso. Always remember that the adjective perigoso changes to perigosa if the subject is feminine.