Medisinen bekjemper sykdommen.

Because -en is the usual definite singular ending for many Norwegian nouns of common gender.

• medisin = medicine

• medisinen = the medicine

• sykdom = disease / illness
• sykdommen = the disease / the illness

So Norwegian often puts the idea of the at the end of the noun, instead of using a separate word like English does.

In Norwegian, the definite article is usually attached to the noun.

So instead of:

• English: the medicine
• Norwegian: medisinen

and instead of:

• English: the disease
• Norwegian: sykdommen

This is one of the first big differences English speakers notice. Norwegian does have other determiners, but in simple cases like this, the noun itself carries the definite ending.

The dictionary forms are:

• medisin = medicine
• bekjempe = to combat / fight / battle
• sykdom = disease / illness

In the sentence:

• medisinen = definite singular form of medisin
• bekjemper = present tense of bekjempe
• sykdommen = definite singular form of sykdom

So this sentence is built from very standard dictionary forms plus normal inflection.

Bekjemper is present tense.

The infinitive is å bekjempe = to combat / to fight.
The present tense is formed as:

• bekjempe → bekjemper

This is very common in Norwegian: many verbs form the present tense with -r or -er.

So bekjemper means:

• combats
• fights
• is fighting

depending on context.

Norwegian does not need a helping verb like does in ordinary present-tense statements.

English:

• The medicine combats the disease.
• or sometimes The medicine fights the disease.

Norwegian:

• Medisinen bekjemper sykdommen.

The verb bekjemper already carries the present-tense meaning by itself.

Yes, in this sentence it is.

The structure is:

• Medisinen = subject
• bekjemper = verb
• sykdommen = object

So it follows a normal Subject–Verb–Object pattern, just like English:

• The medicine / combats / the disease

That makes this sentence fairly straightforward for English speakers.

Yes, you could say sykdom in other contexts, but it would not mean exactly the same thing.

• sykdom = disease / illness in a more general or indefinite sense
• sykdommen = the disease, a specific disease already known or understood from context

So:

• Medisinen bekjemper sykdom.
  = The medicine combats disease / combats illness in general

• Medisinen bekjemper sykdommen.
  = The medicine combats the disease, meaning a specific one

Both are grammatical; they just differ in definiteness.

Bekjempe is a transitive verb, which means it normally takes a direct object.

Here, the object is sykdommen.

So the pattern is:

• noen/noe bekjemper noen/noe
• someone/something combats someone/something

Examples:

• Staten bekjemper kriminalitet. = The state fights crime.
• Legemiddelet bekjemper infeksjonen. = The drug combats the infection.

So in your sentence, the structure is completely normal.

Often yes, but the tone can be a little more formal or technical depending on context.

Bekjempe can mean:

• fight
• combat
• battle
• counteract

In a medical sentence, combat is often a very natural translation.
So Medisinen bekjemper sykdommen sounds quite natural in Norwegian, especially in informational or medical language.

Both are normally common gender nouns in Bokmål.

That is why they take -en in the definite singular:

• en medisin → medisinen
• en sykdom → sykdommen

For English speakers, the important practical point is usually not the label common gender, but remembering which article and ending the noun takes.

It would be:

• En medisin bekjemper en sykdom.

That means something like A medicine combats a disease.

Compare:

• Medisinen bekjemper sykdommen. = The medicine combats the disease.
• En medisin bekjemper en sykdom. = A medicine combats a disease.

This shows clearly how Norwegian marks indefiniteness with a separate article (en) and definiteness with a noun ending (-en).

A useful learner-level guide is:

• be-KJEM-per

The stress is on the middle part: -kjem-.

One tricky thing is kj. In careful standard pronunciation, it is traditionally a soft sound that does not exist in standard English. Many learners approximate it at first, and many native speakers today pronounce it closer to sj, depending on age and dialect.

If perfect pronunciation is not your goal yet, focus first on:

• stressing KJEM
• keeping the final -er light

A simple learner-friendly approximation is:

• SYK-dom-men

The stress is on the first syllable: SYK.

A few notes:

• y in Norwegian is not like English y; it is a rounded vowel that many English speakers find difficult at first.
• The double mm in spelling shows the preceding vowel is short.
• The final -en is the definite ending.

Even if your y is not perfect yet, native speakers will usually understand you from context.

Yes, depending on context, medisinen can mean:

• a specific medicine
• the medicine being discussed
• sometimes the medication as a treatment

So the sentence could refer to:

• one specific drug
• a particular treatment already mentioned
• medicine as a known treatment in the context

As usual, the context tells you how specific it is.

Yes. It is grammatical and natural, especially in informative, educational, or medical contexts.

It sounds a bit more formal or explanatory than everyday conversation, but that is completely normal. In casual speech, people might choose different wording depending on the situation, but Medisinen bekjemper sykdommen is a solid, natural sentence.