not 100% sure but is it this one? https://www.mangago.me/read-manga/i_found_a_family_that_wasn_t_in_my_adoption_plan/
noo, unfortunately not. but thanks for trying （/TДT)/
im so sorry i made a mistake ╥﹏╥ this was the link that i was going to put https://www.mangago.me/read-manga/saving_the_villain_who_was_abandoned_by_the_female_lead/
giiirl!!! this is the one!! i haven't read this in almost 5 yrs so thank you so much for finding it for me(≧∀≦)
i need help looking for this manhwa since my lists are taking forever to return. the mc has blue hair & she was originally working as a maid for a prince. she drank some wine that had poison or somethn in his steed & she turned little. she was later adopted by a family who specializes in poison (initially for research), but they eventually all come to dote on her. this is set in a fantasy world with magic where they believe she has high potential. i think the dad & brother had black hair with red eyes, & there's another brother with blond hair (prob adopted). i believe the ml is the prince. it's all blank from there & i don't even remember if this story was ever completed. please help!