यह दवा कितनी बार लेनी है?

A useful breakdown is:

• यह = this
• दवा = medicine
• कितनी = how many (feminine form)
• बार = times / occasions
• लेनी = to take / to be taken in a feminine form
• है = is

So the sentence structure is literally something like This medicine how many times is to be taken?

लेनी है is a very common Hindi pattern that expresses obligation, requirement, or instruction.

Here, लेनी है means something like:

• has to be taken
• should be taken
• is to be taken

It does not mean is taking.
So this is not a present continuous sentence. It is an instruction-type sentence.

Because कितनी agrees with बार, not with दवा.

In this sentence, कितनी बार means how many times. The noun बार is treated as feminine, so Hindi uses the feminine form कितनी.

That is why you say:

• कितनी बार = how many times

not:

• कितना बार

Here बार means time in the sense of occasion or instance.

So:

• एक बार = one time / once
• दो बार = two times / twice
• तीन बार = three times

In this sentence, कितनी बार means how many times or how often.

Because लेनी agrees with दवा, which is feminine.

In Hindi, in patterns like X लेनी है, the verb form often agrees with the thing that has to be taken/done.

Since दवा is feminine singular, Hindi uses लेनी.

Compare:

• दवा लेनी है = the medicine has to be taken
• if the object were masculine, you would often get लेना, not लेनी

So this feminine ending is an important grammar clue.

Hindi often leaves that information out when it is obvious from context.

This sentence is like a general question about dosage: How many times should this medicine be taken?

If you want to make the person explicit, you can add it:

• मुझे यह दवा कितनी बार लेनी है? = How many times do I have to take this medicine?
• आपको यह दवा कितनी बार लेनी है? = How many times do you have to take this medicine?

So the original sentence is natural even without an explicit subject.

Because दवा is the direct object of लेना, and direct objects in Hindi do not always take को.

With inanimate things like medicine, book, water, and so on, Hindi very often leaves out को.

So:

• दवा लेनी है = natural
• दवा को लेनी है = not natural here

English learners often expect a marker like to or for, but Hindi does not need one in this sentence.

Hindi usually does not form questions by inverting the verb the way English does.

English:

• How many times should I take this medicine?

Hindi:

• keep the normal order
• put the question word in the relevant place
• leave है at the end

Compare:

• यह दवा दो बार लेनी है। = This medicine has to be taken twice.
• यह दवा कितनी बार लेनी है? = How many times does this medicine have to be taken?

So Hindi question formation is often simpler than English word order.

Yes. दवा and दवाई both mean medicine.

In everyday speech, both are common. दवा is shorter, while दवाई is also very natural and familiar.

So you may hear:

• यह दवा कितनी बार लेनी है?
• यह दवाई कितनी बार लेनी है?

Both are acceptable.

Yes, depending on the type of medicine.

लेना is the most general verb and works very well for medicine overall. It is like English take medicine.

But Hindi can also use more specific verbs:

• गोली खानी है = the pill/tablet has to be taken (literally eaten)
• सिरप पीना है = the syrup has to be drunk
• दवा लेनी है = general and very common

So लेनी is a safe, broad choice here.

You can say:

• मुझे यह दवा दिन में कितनी बार लेनी है?

If you want a more general version without I, you can say:

• यह दवा दिन में कितनी बार लेनी है?

Here दिन में means in a day / per day. This is a very useful addition when asking about dosage.