De or het gastrologie?

The correct Dutch article is:

de gastrologie

Rule Words ending in -logie: always de. See the rule
Meaning (Dutch) wetenschap van de maagziekten

How to use gastrologie

the gastrologiede gastrologie
this gastrologiedeze gastrologie
that gastrologiedie gastrologie
our gastrologieonze gastrologie
your gastrologiejouw gastrologie
every gastrologieelke gastrologie
which gastrologie?welke gastrologie?
a big gastrologie / the big gastrologieeen grote gastrologie, de grote gastrologie

Meaning, plural, diminutive, pronunciation and translations: WikiWoordenboek (Dutch Wiktionary) (CC BY-SA 4.0). Example sentences: Tatoeba (CC BY 2.0 FR).