Learn Hardcore Polish: Lekarz mówi, że nie powinniśmy długo chorować, jeśli bierzemy lekarstwo. - The doctor says that we should not be ill for long if we are taking the medicine.

Lekarz mówi, że … = The doctor says that …
The whole part starting with że is a clause dependent on mówi (“says”), so it must be separated by a comma.
Unlike in English (where the comma before “that” is usually wrong), in Polish this comma is correct and required here.

What exactly does że mean here? Is it the same as English “that”?

Yes. że is a conjunction and here it works very much like English “that” in reported speech:

Lekarz mówi, że … = The doctor says that …

You cannot normally omit że the way you can often omit “that” in English (“The doctor says we shouldn’t…”). In everyday Polish speech people sometimes drop it in very informal phrases, but in standard language you keep it.

Why is the negation nie before powinniśmy and not before chorować?

Powinniśmy is a modal verb (like “should”), so the negation usually goes on the modal, not on the main verb:

nie powinniśmy chorować = we should not be ill

If you put nie before chorować (powinniśmy nie chorować), it sounds strange or very unnatural, like “we should not be ill-ing” instead of simply “we shouldn’t be ill”.
So:

nie powinniśmy chorować – normal, natural
powinniśmy nie chorować – theoretically possible but stylistically awkward and rarely used.

What does powinniśmy mean, and how is it formed?

Powinniśmy means “we should / we ought to”.

It’s the 1st person plural form of powinien (“should, ought to”):

powinien – he should
powinnam – I (female) should
powinienem – I (male) should
powinniśmy – we should
powinniście – you (plural) should

The ending -śmy marks “we” (1st person plural). So my (we) is usually omitted:

(My) powinniśmy długo chorować – “We should be ill for a long time”
(My) nie powinniśmy długo chorować – “We shouldn’t be ill for long”

Where is the word “we”? Why is there no my in the Polish sentence?

The subject “we” is included inside the verb ending -śmy in powinniśmy and bierzemy. Polish verb forms usually tell you who the subject is:

(my) bierzemy – we take
(oni) biorą – they take

Because of that, Polish often omits personal pronouns (ja, ty, my, wy, on, ona, oni), unless you want to emphasize or contrast something.
So adding my is possible but not necessary:

My nie powinniśmy długo chorować – “We (in particular) shouldn’t be ill for long.”

Why is it długo chorować and not chorować długo? Does the word order matter?

Both długo chorować and chorować długo are grammatically correct. Polish word order is quite flexible, especially with adverbs.

Here, nie powinniśmy długo chorować is the most neutral, common order: adverb (długo) before the verb (chorować).
If you say nie powinniśmy chorować długo, it might sound slightly more marked or rhythmic, but the meaning is the same in this simple sentence.

So in practice:

długo chorować – “be ill for a long time” (very natural)
chorować długo – also possible, just less typical here.

What is the difference between chorować and być chorym?

Both relate to being ill, but they are used somewhat differently:

chorować – literally “to be ill / to suffer from an illness” as an activity or state over time.
- On choruje od tygodnia. – He has been ill for a week.
być chorym – “to be sick/ill” (using the verb to be
- an adjective).
- On jest chory. – He is ill.

In your sentence, długo chorować focuses on the duration of the illness, which fits well with długo (“for a long time”). Saying nie powinniśmy długo być chorzy would be understood, but it’s less idiomatic.

Why is it Lekarz mówi and not Lekarz powiedział? Does it affect the English translation?

Both are possible, but they have different nuances:

Lekarz mówi, że… – literally The doctor says that…
- Suggests something the doctor says generally, repeatedly, or right now.
Lekarz powiedział, że… – The doctor said that…
- Refers to one particular moment in the past.

In English you would normally translate Lekarz mówi, że… as “The doctor says (that) …” and Lekarz powiedział, że… as “The doctor said (that) …”.
Polish does not use past tense here in the same obligatory way English often does; the present tense mówi is natural even for “reported advice” that still holds.

Why does the sentence use jeśli bierzemy lekarstwo and not a future tense like jeśli będziemy brać lekarstwo or jeśli weźmiemy lekarstwo?

In Polish, as in English, you normally use the present tense in the if-clause when you talk about a general condition:

If we take the medicine, we won’t be ill for long. (present in English)
jeśli bierzemy lekarstwo, nie powinniśmy długo chorować (present in Polish)

You can use future forms (będziemy brać, weźmiemy) for more specific future situations, but they sound more concrete and less “general rule”:

Jeśli będziemy brać lekarstwo, szybko wyzdrowiejemy.
If we (keep) taking the medicine, we will get well quickly.

In your sentence, bierzemy expresses a general condition, so present tense is natural.

What is the difference between brać and wziąć? Why is it bierzemy lekarstwo and not weźmiemy lekarstwo?

Brać and wziąć are aspectual pairs:

brać – imperfective: to take (in general, repeatedly, or as an ongoing action)
- bierzemy lekarstwo codziennie. – We take the medicine every day.
wziąć – perfective: to take once, to have taken (completed action)
- weźmiemy lekarstwo teraz. – We will take the medicine now (once).

In jeśli bierzemy lekarstwo, the speaker is talking about the general act of taking the medicine as a condition (habit or rule), so the imperfective brać (bierzemy) is more appropriate than the single, completed act weźmiemy.

Why is there a comma before jeśli in …, jeśli bierzemy lekarstwo?

Jeśli introduces another subordinate clause (a conditional clause), so Polish punctuation requires a comma:

Nie powinniśmy długo chorować, jeśli bierzemy lekarstwo.

In English, we also often use a comma before “if” when the “if”-clause comes second:

We shouldn’t be ill for long, if we take the medicine.

If the jeśli-clause came first in Polish, you would still use a comma:

Jeśli bierzemy lekarstwo, nie powinniśmy długo chorować.

Can I change the word order to Lekarz mówi, że jeśli bierzemy lekarstwo, nie powinniśmy długo chorować?

Yes, that sentence is also correct and natural.

Polish allows you to move the jeśli-clause inside the że-clause:

Lekarz mówi, że nie powinniśmy długo chorować, jeśli bierzemy lekarstwo.
Lekarz mówi, że jeśli bierzemy lekarstwo, nie powinniśmy długo chorować.

Both mean the same. The second one slightly emphasizes the condition (if we take the medicine) earlier in the reported speech, but the difference is subtle.

What is the difference between lekarstwo, lek, and medycyna?

All are related to medicine, but they’re used differently:

lekarstwo – common, everyday word for “medicine” or “medication” (a remedy).
- brać lekarstwo – to take medicine
lek – more technical/formal word, often in medical or pharmaceutical contexts; can mean a specific drug.
- lek przeciwbólowy – painkiller
medycyna – “medicine” as a field of study or science, not a pill.
- studiować medycynę – to study medicine (at university)

So in this sentence, lekarstwo is the natural choice.