Warnings and Consequences
When you need to give urgent advice or a command, it helps to explain what will go wrong if your instructions aren't followed. To express "otherwise" or "or else" in Russian, use the conjunctions а то and не то.
Both phrases are used interchangeably to connect an instruction to a negative consequence. You will typically see an imperative verb (a command) in the first half of the sentence, followed by а то or не то, and then the negative result—which is often a perfective verb in the future tense to show exactly what will happen.
| Hurry up, or we'll be late. | Поторопись, а то мы опоздаем. |
| Don't drink this water, or you'll get poisoned. | Не пей эту воду, а то отравишься. |
You can use не то in exactly the same way to issue a warning or outline a threat.
| Never park here, or you'll get fined. | Никогда здесь не паркуйся, не то оштрафуют. |
| Put on a warm coat, or you'll freeze. | Надень тёплое пальто, не то замёрзнешь. |
Rules and Obligations
These conjunctions are not limited to direct commands. You can also use them to explain the severe consequences of ignoring general rules, safety guidelines, or basic necessities.
Instead of an imperative, the first half of the sentence often features obligation words like нужно or надо (one needs to / it is necessary), or the short adjective должен (must / should).
| One needs to turn off the iron, otherwise the house will burn down. | Нужно выключать утюг, а то дом сгорит. |
| Nobody should swim in this river, or they will drown. | Никто не должен плавать в этой реке, не то утонет. |
| People need to rest, or else they get sick. | Людям надо отдыхать, а то они заболеют. |