Elle dit que si je n’ai plus d’appétit ce soir, je dois quand même manger un peu avant d’avaler le comprimé.

Que introduces a reported statement. It means that.

So:

• Elle dit que... = She says that...

In English, that is often optional, but in French que is usually kept.

After si meaning if, French normally uses the present tense, not the future, for a real condition.

So French says:

• si je n’ai plus d’appétit ce soir
  literally: if I don’t have any appetite tonight

Even though the situation is in the future from the speaker’s point of view, French still uses the present after si.

A very common rule is:

• si + present, then another tense in the main clause

So:

• Si je n’ai plus faim, je dois manger un peu.

Not:

• Si j’aurai... ❌

Ne... plus means no longer or not anymore.

So:

• je n’ai plus d’appétit = I no longer have an appetite / I’m not hungry anymore

It is different from:

• ne... pas = simple negation, not
• ne... jamais = never
• ne... rien = nothing

In everyday spoken French, people often drop ne, so you may hear:

• j’ai plus d’appétit

But in standard written French, ne is kept:

• je n’ai plus d’appétit

This is because French often changes the partitive article after negation.

Compare:

• J’ai de l’appétit. = I have an appetite.
• Je n’ai pas d’appétit. = I don’t have an appetite.
• Je n’ai plus d’appétit. = I no longer have an appetite.

So after pas, plus, and similar negative expressions, de l’ often becomes de / d’.

That is why d’appétit is the normal form here.

Ce soir means this evening or tonight.

• ce = this
• soir = evening

French uses ce soir very naturally for something happening later the same day.

Examples:

• Je travaille ce soir. = I’m working tonight.
• On se voit ce soir ? = Shall we see each other tonight?

Here quand même means something like:

• all the same
• even so
• anyway
• still

It shows contrast:

• even if I do not feel hungry,
• I still have to eat a little.

So:

• je dois quand même manger un peu
  = I still have to eat a little anyway / all the same

This is a very common French expression.

Je dois means I must / I have to. It expresses a stronger obligation.

Je devrais means I should / I ought to. It sounds less strict and more like advice.

So the sentence suggests a real instruction:

• je dois manger = I have to eat

If it said:

• je devrais manger

that would sound more like a recommendation than a requirement.

Un peu means a little or some. It is the normal everyday way to say a small amount.

• manger un peu = eat a little

Peu by itself can mean little / not much, but it does not sound the same.

Compare:

• Je mange un peu. = I’m eating a little.
• Je mange peu. = I eat little / I don’t eat much.

So in this sentence, un peu is the natural phrase because it means at least a small amount.

After avant, French uses de before an infinitive:

• avant de + infinitive

So:

• avant d’avaler = before swallowing

Because avaler begins with a vowel, de becomes d’:

• de avaler → d’avaler

This is the normal construction.

A useful comparison:

• avant de manger = before eating
• avant de partir = before leaving

Prendre un comprimé means to take a tablet/pill in the medical sense.

Avaler means to swallow.

So the sentence is focusing on the physical act of swallowing the tablet:

• avant d’avaler le comprimé = before swallowing the tablet

If it said avant de prendre le comprimé, that would mean before taking the tablet more generally.

Both can make sense, but avaler is more specific.

Yes. Un comprimé is a common word for a tablet or pill, especially in medical or pharmacy contexts.

It is more specific than some other words:

• comprimé = a tablet
• gélule = a capsule
• pilule = pill, but often used in some specific contexts

So avaler le comprimé sounds like a normal medical instruction.

In ne... plus meaning no longer / not anymore, plus is usually pronounced plu, with the final s silent.

So:

• je n’ai plus d’appétit sounds roughly like zhuh nay plu dah-pay-tee

This is different from plus meaning more, where the final sound is often pronounced:

• plus de temps = more time

So learners often need to watch both the meaning and the pronunciation of plus.