why is it ironic the way mama elena dies?

Mama Elena is struck by bandits and in need of constant care. She is paranoid that Tita is trying to poison her. Really nobody can stand Mama. One month later Mama Elena dies from pains and spasms. Tita and John discover a bottle of ipecac in her dresser and conclude that it caused Mama Elena’s death. Ironically Mama claims people are trying to poison her yet she poisons herself with the ipecac.