Thuốc này rất độc.

This medicine is very toxic.

Breakdown of Thuốc này rất độc.

• rất: very
• này: this
• thuốc: the medicine
• độc: poisonous; toxic

Questions & Answers about Thuốc này rất độc.

Why does này come after thuốc instead of before it?

In Vietnamese, demonstratives like này (this) usually come after the noun.

So:

• thuốc này = this medicine
• not này thuốc

This is a very common pattern:

• người này = this person
• nhà này = this house
• xe này = this vehicle

So the order is different from English: noun + this/that.

Why is there no word for is in this sentence?

Vietnamese often does not use a verb like is when an adjective is the predicate.

So:

• Thuốc này rất độc. literally follows the pattern This medicine very toxic.

That is completely normal in Vietnamese.

You would usually use là for things like identification or definition, not before ordinary descriptive adjectives.

For example:

• Đây là thuốc. = This is medicine.
• Thuốc này rất độc. = This medicine is very toxic.

So in your sentence, leaving out is is correct.

What does rất mean, and where does it go?