deleterious
Synthetic detergents are affected deleteriously by the hardness of the water.
Patients in country areas will be deleteriously affected by this legislation.
A corporal at seventeen and captain at twenty-three, his advancement had been deleteriously rapid.

SMART Vocabulary: related words and phrases

Dangerous and harmful
adverse
adverse conditions
adverse effect
adverse publicity
adverse reaction
destabilizing
destructive
destructively
destructiveness
detrimental
inimically
injurious
injuriously
insidious
insidiousness
self-destruction
self-destructive
stinking thinking
toxicity
treacherously

You can also find related words, phrases, and synonyms in the topics:

Serious and unpleasant