Envenena means "poisons" or "contaminates." It's a strong and evocative verb that immediately grabs attention, as it's not a word commonly found in everyday romantic lyrics.
In this song, the singer uses it to describe how the memory of his past love, despite being painful, still "poisons" his heart and even the song itself. This metaphorical use of "envenena" highlights the toxic yet inescapable hold this person has over him, making it a compelling word choice.
This song, "No Puedo Olvidarla" by Binomio de Oro de America, is all about that intense, almost obsessive feeling when you just can't get someone out of your head, even when you know they're bad for you. The singer describes this woman as "el sueño de aquellos que pueden respirar" [the dream of those who can breathe], but then immediately warns that "Te duermes en sus brazos sin saber que morirás" [You fall asleep in her arms without knowing you'll die]. It's a really dramatic way to say she's captivating but dangerous!
He admits that her "veneno esta presente aquí en el corazón" [poison is present here in the heart], and even though she's hurt him, he still loves her. He tells his friend, "Siento decepcionarte es demasiado tarde ya / Si intentas que la olvide en el intento morirás" [I'm sorry to disappoint you, it's too late now / If you try to make me forget her, you'll die trying]. It's clear he's completely under her spell, even justifying her past lies. He can't imagine being with anyone else, saying "No me nace estar con otra / El corazón no me miente" [It doesn't occur to me to be with another / My heart doesn't lie]. He's stuck in this cycle, hoping she'll still want him, even after she's "vendió mi futuro / A un pasado muy oscuro" [sold my future / To a very dark past]. It's a powerful and relatable look at love that just won't let go.