Learn Finnish: Onko akupunktio turvallinen vaihtoehtoinen hoito? - Is acupuncture a safe alternative treatment?

It comes from the noun vaihtoehto (alternative or option), which is a compound of vaihto (exchange or change) and ehto (condition or term). The -inen suffix turns this noun into the adjective vaihtoehtoinen (alternative).

Why are the describing words and the noun (turvallinen vaihtoehtoinen hoito) in the nominative case rather than the partitive?

This is a basic 'A is B' classification sentence where the subject (akupunktio) is being equated to a singular countable noun (hoito). Because we are talking about it as a single conceptual category rather than an undefined mass or part of a whole, the noun and its adjectives stay in the basic nominative case.

Is it normal to stack adjectives like turvallinen vaihtoehtoinen hoito without any commas?

Yes! Just like in English, if the adjectives belong to different descriptive categories (here, a subjective quality like turvallinen followed by a classifying type like vaihtoehtoinen), you can stack them directly before the noun without needing a comma or the word ja (and).

Why use hoito here instead of the verbal noun hoitaminen?