Medicus dicit medicamentum amarum esse, sed utile esse.

Because after dicit Latin is using an indirect statement construction.

In English, we often say:

• The doctor says that the medicine is bitter.
• The doctor says that the medicine is useful.

In Latin, after verbs like dicit (says), the usual pattern is:

• accusative + infinitive

So instead of a normal clause with a finite verb, Latin uses:

• medicamentum amarum esse
• literally: the medicine to be bitter

Here, medicamentum is in the accusative because it is the subject of the infinitive esse inside an indirect statement.

In this sentence, medicamentum could look the same in both nominative and accusative, because it is a neuter second-declension singular noun.

For neuter second-declension nouns:

• nominative singular: -um
• accusative singular: -um

So the form is identical.

You know it is accusative here from the grammar of the sentence:

• Medicus is the nominative subject of dicit
• after dicit, Latin normally uses an indirect statement
• therefore medicamentum is functioning as the accusative subject of esse

Because amarum agrees with medicamentum.

Medicamentum is:

• singular
• neuter
• accusative here

So the adjective must match it in:

• gender
• number
• case

That gives:

• medicamentum amarum esse

If the noun were masculine singular, you would expect amarus in the nominative, or amarum in the accusative. But since medicamentum is neuter, amarum is the correct form.

Because utilis, utile is a third-declension adjective with different masculine/feminine and neuter forms.

Its dictionary forms are:

• masculine/feminine: utilis
• neuter: utile

Since medicamentum is neuter singular, the adjective must be neuter singular too:

• medicamentum utile esse

So:

• utilis = masculine or feminine
• utile = neuter

Yes, Latin can sometimes leave out the second esse, especially when the structure is clear.

So both of these are possible:

• Medicus dicit medicamentum amarum esse, sed utile esse.
• Medicus dicit medicamentum amarum esse, sed utile.

The repeated esse is not wrong at all. In fact, it can make the parallel structure clearer:

• bitter to be
• but useful to be

With sed, repeating esse can help mark the contrast neatly.

Because classical Latin usually does not use that in this kind of sentence.

English often says:

• The doctor says that the medicine is bitter.

Latin usually prefers the accusative + infinitive construction instead:

• Medicus dicit medicamentum amarum esse.

So the idea of English that is built into the grammar of the indirect statement, rather than expressed by a separate word.

It breaks down like this:

• Medicus = the doctor
• dicit = says
• medicamentum amarum esse = that the medicine is bitter
• sed = but
• utile esse = to be useful / that it is useful

So the main clause is:

• Medicus dicit

And everything after that is what the doctor says.

More precisely, the indirect statement has one subject:

• medicamentum

and two predicate adjectives with infinitives:

• amarum esse
• utile esse

Because it is understood from the first part.

Latin often avoids repeating a word when the meaning is already clear. Here the same medicamentum goes with both adjectives:

• medicamentum amarum esse
• (medicamentum) utile esse

English does something similar:

• The doctor says the medicine is bitter, but useful.

We do not need to repeat the medicine is in full if the meaning is obvious.

Yes. That would be a direct statement, not an indirect one.

• Medicamentum amarum est, sed utile est.
  = The medicine is bitter, but it is useful.

• Medicus dicit medicamentum amarum esse, sed utile esse.
  = The doctor says that the medicine is bitter, but useful.

So the difference is:

• est = finite verb in a normal statement
• esse = infinitive used in indirect statement after dicit

Yes, Latin word order is more flexible than English word order because the endings show grammatical relationships.

This sentence could be rearranged in other ways without changing the core meaning, for example:

• Medicus dicit amarum esse medicamentum, sed utile esse.
• Medicamentum medicus dicit amarum esse, sed utile esse.

The given order is very natural and clear:

• first the speaker: Medicus
• then the reporting verb: dicit
• then the content of what is said

So the word order helps readability, but the endings carry the grammar.

Sed means but and introduces a contrast.

The two ideas are:

• the medicine is bitter
• the medicine is useful

These are not logical opposites, but they are contrasting ideas in context: something unpleasant in taste can still be beneficial.

So sed highlights that contrast:

• bitter, but useful

Yes, Latin sometimes compresses repeated elements, and a writer might choose a more compact phrasing. But with sed, keeping both parts balanced is very natural:

• amarum esse, sed utile esse

That repeated structure makes the contrast especially clear.

So the sentence as given is a good, straightforward example of how Latin expresses two linked descriptions inside one indirect statement.

They are in the accusative singular neuter, because they agree with medicamentum, which is the accusative subject of the infinitive in indirect statement.

Even though in English we think of bitter and useful simply as predicate adjectives, in Latin they still agree with the noun they describe.

So:

• medicamentum = accusative singular neuter
• amarum = accusative singular neuter
• utile = accusative singular neuter

This agreement is one of the key things to notice in the sentence.